Dude, I know nothing about game developing, so I will not comment about all the new damage stuff.
Now talking as an RPG player.
1 - You have several good concepts and ideas here, mainly in the skills.
2 - But when you put it all together, it becomes overpowered. This leads into a paradox:
A - This is a superior kind of being, so it’s natural to be overpowered. But how to balance it with all other masteries?
B - This is a regular being, so it’s natural to be balanced with the other masteries. Then you need a massive nerf in the overall concept.
3 - You need to work in your numbers. There is too much “100%”. In all RPGs you don’t have perfect skills: or the skill is weak and can be continuous casted, or the skill is strong and needs cooldown/charge or deal with low chances of activation. This promotes balance.
4 - I think this game deserves a paladin, monk or any kind of “holy” or “spiritual” warrior, and there is a lot of your concepts that can be incorporated into this.
For a regular paladin, your cosmic-styled skills can be adapted into “blessings” and the damage can be based on fire, lightning and aether.
For a monk, you can still use the cosmic concepts, add some chakras stuff into the mix. The damage can be based on fire/cold/lightning or on aether/piercing/caos.
You can even think about some kind of “starchild” class and use it with little changes, but you will have to nerf your concept and I also don’t know how to fit it into the lore.
5 - As I said, there are tons of great ideas in your post, but the overall concept it’s huge and overpowered. You are trying to fit an watermellon in the middle of the apples.
6 - BUT, if we were talking about a game that relies on masteries beyond the human level, I would really enjoy to play this class or at least see it as the main enemy. 