this has probably been said but since leo's whole thing is being the "seventh wheel" and "alone" his ending shouldve been him finding who he was and being content with his friends without needing a lover right. like it could be resolved with PURE PLATONIC LOVE right.
as for calypso. like her whole thing is stuck on the island without any company so what if her ending was just JOINING THE HUNTERS OF ARTEMIS because THEN she wouldnt be LONELY and also her falling for the heroes on her island was JUST BECAUSE SHE FELT LIKE SHE HAD TO?? i dont think i phrased all this right but i hope i carried my message clearly enough across