As a red mist main i think the key to nerfing onrush is the fact you cant do it twice in a row, and upwards/downwards di. Onrush already usually grounds DI down opponents to -2 frames which means you can only continue combo by using burst cancel, but upwards di doesnt hit the opponent up enough for your other options to no longer hit when it probably should. onrush should also probably have slightly less hitstun frames in general so you cant just double jump full distance to reposition afterwards. in exchange you can buff descend to let it help you continue combo after an anti up di sunder instead of just only continuing the combo against wallsplat (i dont think this is necessary because aerial prey is already balanced and finicky enough to make playing around it interesting but it is kinda a shame how descend is just for when you ♥♥♥♥♥♥ up your combo and need to get back your air options by wasting your last one)

also the aerial ego options definitely are lacking, the current air leveling slash is high damage for combos and its good that its not just the ground version because that would be broken since ground levelling slash is really strong, but air upstanding slash is kinda dog since it has really long endlag and no hyperarmor and you can (usually) just position sunder so that only the second hitbox hits to punish block

BTW rlly based work on the kether updates o7