🤷 It's a thing that exists I guess? I mean, we know nothing about what their relationship was like so I don't really have an opinion. The whole father tries to get rid of his children and mother turns against him thing was already done before them by Gaia and Ouranos (in a cooler/funnier way at that), so they don't have much going for them in the uniqueness department, nor do they interact ever again after Kronos is deposed by Zeus. Even the very little we get to know about their relationship is not particularly appealing, since when relating the union of Kronos and Rhea Hesiod describes her as tamed/subjected/subdued (δμηθεῖσα) by him, the same verb used in the Theogony to describe Thetis' marriage with Peleus (which is a forced one in the overwhelming majority of sources) and of Medea with Iason (again a union arranged by the gods), as well as Zeus overpowering Kronos and Typhoeus and Herakles defeating the Nemean Lion.

The one story of theirs I find intriguing is the one in which they fight and defeat Ophion and Eurynome, the previous rulers of the cosmos. That is pretty cool and unusual.

“When the sixth [child] is about to arrive, Rheia appeals to Gaia and Ouranos — who seem now on more amiable terms with each other— for a plan to save him. Following their counsel, she goes to Lyktos on Krete to deliver Zeus, and hands him over to Gaia to rear, while she herself gives Kronos a stone wrapped in swaddling clothes to swallow (Th 463–91). Hesiod adds to this account only that Zeus grew swiftly, but the Eumolpia of "Mousaios" says that he was given to Themis, his aunt, who in turn gave him to Amaltheia, who had a goat nurse him (2B8, apud Katast 13). The account of Ps-Eratosthenes from which this last information is drawn goes on to claim that the goat in question was a child of Helios, with an appearance much feared by the Titans, who requested Gaia to hide her in a cave on Krete. Gaia did so, but also gave her into Amaltheia's safekeeping. Subsequently, in this same account, Zeus is advised that the skin of that goat will protect him in his battle with the Titans, being invulnerable and much feared by them (it has as well a Gorgoneion on its back). Our epitome of the Katasterismoi goes no further than this, but Hyginus (Astr 2.13.4) provides the clearly intended conclusion that this skin is the aigis, and both Hyginus and the Germanicus scholia make it the source of Zeus' epithet aigiochos.

Kallimachos (Hymn 1.47–48) seems the first to assign the name "Amaltheia" to the goat itself; so too Eb Iliad 15.229, which offers much the same information as Ps-Eratosthenes, with the addition that Themis was the source of the advice to use the skin of the goat as protection. Ovid (like most other authors) returns us to the idea that Amaltheia was the owner of the goat; he adds, however, that the goat broke one of her horns against a tree, and that Amaltheia carried the horn, filled with fruits, to the child Zeus (Fasti 5.111-28). This seems the earliest preserved source we have to relate this origin of the horn of plenty, but already in the Archaic period Anakreon has referred to "the horn of Amaltheia" as something highly desirable (361 PMG; likewise Phokylides (fr 7 Diehl]), and Pherekydes says that it had the power to furnish whatever food and drink one might desire (3F42). ...

Returning to the matter of Zeus' infancy, we find in the Epimenidean Theogony that the god turns himself into a snake and his nurses into bears to deceive Kronos, and is nursed together with Aigikeros, who aids him against the Titans (3B23, 24). Ps-Eratosthenes, our source for the latter point, adds that this Aigikeros was sprung from Aigipan with Aix (or "the goat") as mother, and had horns and the tail of a fish, the latter appropriately since he used a conch shell to frighten the Titans (Katast 27). He was, of course, made into a constellation for his services, Aigikeros to the Greeks, Capricornus to the Romans (Astr 2.28).

Far better known than this figure, however, and probably much more crucial to Zeus' safety, are the Kouretes, the attendants of his mother who supposedly clashed their weapons to drown out his cries. If Korinna could be dated to the Archaic period, she would constitute valuableearly evidence for their existence, for she says that they hid the god from Kronos (654 PMG). Otherwise we have nothing at all until the poem of“ Epimenides on the birth of the Kouretes and Korybantes (a poem that may have prefaced the Epimenidean Theogony), and nothing of any substance until Euripides. This last poet's Kretes links the Kouretes with Idaian Zeus, Zagreus, and the "mountain mother" (fr 472 N2) while Bakchai 120–34 may allude to their protective role. For the concrete action of concealing Zeus' infant cries by the clashing noise of their weapons, however, our first source is again Kallimachos (Hymn 1.51–53). ... Both Kallimachos (Hymn 1.46) and Apollonios (3.133) speak too of a nurse Adrasteia (another name for Nemesis?), and Apollodoros adds to her Ida, both as daughters of Melisseus (ApB 1.1.6-7; see Appendix A for possible Orphic sources). In Hyginus, the account of the noisemaking of Kouretes or Korybantes is prefaced by a story in which Kronos has cast Poseidon into the sea and Hades down to the Underworld, rather than swallowing them; Hera (also not swallowed) then asks her mother to give her the child Zeus when he is born, and Rheia substitutes the stone for Kronos to swallow (Fab 139). Kronos soon discovers the trick but cannot find the child, suspended as he is in a cradle between sky, earth, and sea by Amaltheia.””

 - Early Greek Myth: A Guide to Literary and Artistic Sources by Timothy Gantz

"As for Rheia, she appears subsequently in the Homeric Hymns at Leto's delivery of Apollo, and as Zeus' messenger to announce the settlement regarding Persephone to Demeter (HAP 93; HDem 441–43), while in Bakchylides she is the one to bring Pelops back to life (fr 42 SM). Her identification with Kybele must be subsequent to the time of that divinity's entry into the Greek world. As far as literature is concerned, the name "Kybele” first appears in Aristophanes ' Omithes (876–77), where she is, like Sabaizos, of Phrygian origin and mother of gods and men. But the cult of the“ Meter " is clearly much older, as evidenced by an early Mêtrôon in the Athenian Agora and by Pindar'sreference in a dithyramb to the Great Mother for whom drums sound on Olympos (fr 706.8–9 SM). Euripides' Kretes (fr 472 N’, as above) mentions this Meter in connection with Idaian Zeus and Zagreus, and the Bakchai makes the link almost certain by naming Rheia as co-inventor of the Phrygian drums with which are celebrated the rites of the Great Mother Kybele (Bkch 58–59, 78–79).

But there were also other views on the Greek divinity most suited to represent the Mother: Euripides' contemporary, Melanippides, seems to have equated her with Demeter (764 PMG), and Euripides himself in the Helen calls Demeter (as she searches for her daughter) the "mountain mother of the gods", with a characterization of her worship and attributes unmistakably that of Kybele (Hel 1301–52). Such a link between Kybele and Demeter, rather than Kybele and Rheia, may have arisen from the Phyrigian's role as mother of all the gods (indeed, the mother of all life), in contrast to Rheia, the mother only of the Olympians. But we shall see in Appendix A that the situation is still more complicated, for the Derveni papyrus now suggests that the fusion of Rheia and Demeter as the mother of Zeus and of his daughter Persephone in Orphic theogonies may go back to the beginning of the fifth century."

- Early Greek Myth: A Guide to Literary and Artistic Sources by Timothy Gantz

“Rhea, in sooth, is both the Fountain and the Flood of the blest Knowing Ones; for she it is who first receives the Father’s Powers into her countless Bosoms, and poureth forth on every thing birth [-and-death] that spins like to a wheel.” (trans. G. R. S. Mead, 1908)

Orphic Fragment 132

“That Dîmítîr (Δημήτηρ), Orphéfs indeed, by saying she is the same as Rǽa (Ῥέα), he means that when she is aloft with Krónos (Κρόνος), she is known as Rǽa, but when coming forth and generating Zefs (Ζεὺς), she is Dîmítîr. For he says: “ ‘Formerly being (called) Rǽa, when she came to be the mother of Zefs, she became Dîmítîr.’”

Orphic Fragment 145

I really don't know why anyone would ever imagine Hera and Rhea as having a close and loving relationship. Why would they be fond of each other? Hera has no reason to even consider Rhea a mother. Depending on the version, the three daughters of Asterion, Temenos, Makris or Tethys and Okeanos are much more likely to have her affection, since they actually raised her. Rhea obviously doesn't approve of Hera's actions regarding the children of Zeus, as demonstrated by her presence at the birth of Apollon and by the fact that she cured Dionysos of madness. Given Rhea's experiences with her own children and Kronos, this makes perfect sense and it is clear that Hera resembles her father much more than she does her mother. Also, we have no account of Rhea ever supporting, defending or comforting Hera in any way. In contrast, we have Temenos supporting her decision to leave Zeus, and we have Tethys trying to make her feel better by persecuting poor Kallisto. To be fair, Rhea appears very little in the myths and thus doesn't have many opportunities to interact with her children. Still, she seems to be relatively close to Demeter since she was the one who convinced her to return the earth's fertility and rejoin the other gods and they are also described as being glad to see each other. Note, though, that Rhea did not do this of her own initiative, but at the behest of Zeus. She didn't actually support Demeter in her grief, and one of her main concerns in her speech to her daughter seems to be making sure that she stops being angry with the one who sold Persephone off with no care about how that would affect Demeter. If anything, of all her children, she is in all probability closest to Zeus.