I just thought about something:
Since you’ve palpatine given red lightning as symbol for absolute power and darkness, i feel it wouldn’t be enough for rey to beat him with the help of past jedi. Perhaps you’d consider to give her sith eyes for a brief moment. So she taps willingly into the dark side to prevail against palpatine. My reasoning behind it would be that she tapped into her dark side before (previous movie and neverargreats „starlight project“) but out of fear or anger. This way it would manifest here growth as force user and neither hang on to the dogma of jedi or sith.

*original idea with the sith eyes is from „peregrine“