I had a headcanon that kinda deals with SPoP and some of the other incarnations of He-Man. Trying to justify them in a relatively singular universe...
We know Horde Prime is beyond obsessed with making the universe in his image, and keeps his past selves as backup memory storage. Ideally, that's kinda dumb since they are already useless and you could make backups of your memory, so why?
The answer, he ISNT the real Prime. He is Kec-Tor-Kur, the true original Hordak that was defeated long ago by King Grayskull and was nearly killed, being split in two. Every aberrant clone takes the name Hordak, ironically being closer to his true self, but the current Prime is subconsciously looking to be more like his older brother, the True Horde Prime who exists locked in an extra dimensional prison.
Also, I headcanon the First Ones are a splinter group from the Eternian Elders who felt science trumped magic. Their leader (cant think of his name but he was the traitor in the Eternity War comics) watched Veena give her life to create the Gem of Protection in order to create She-Ra, and so...he made a mockery of it, a controller. The sword in PoP is a mockery of the true relic that exists deep in Grayskull, waiting for Adora...
This is very interesting and well thought out. This has the makings of a really epic AU. I think you should write it! It'll be fun to read!