2 Similarly the Ghost AI of Jor-El tried playing with portals, he failed, but there is an extradimensional city called Infinite City that has portals that kidnap people from all over the place, to a city with advanced technology and magic where Kryptonese is the official language, where the AI of Jor-El runs the place, with his clone son Kal-El, aka the Warden, in the comics.
Rao isn't just the sun god, he's the creator of the kryptonian people and supposedly the universe according to Kryptonian mythology. He got upgraded over the years ala Ra.
The only god of death I'm aware of is
Cythonna, the Kryptonian goddess of ice, fear, darkness, and death, who was banished by Rao and his children to the void between existinces, where the unforgiving dead go to her, that is until her banishment ended after Krypton's destruction.
Ironically, Cythonna made the Kryptonians athiests, she cooled their spirituality, although if that was universally effective depends on the iteration.
In the New Krypton storyline the priesthood was still quite the political power, for example.
Ahriman, admittedly not the most reliable source, claimed that Rao abandoned Krypton and colonized Earth, fathering the gods of Earth. When Superman asked if he had been telling the truth the godly UN, consisting of ZOAT- Zeus, Odin, Ale, and Toth, he got a very angry answer.
If Rao did abandon his planet, he might have taken an entourage.....