The best solution would ever be just scaling the level while letting you retain your kit.

I know there might be an issue w power when paired with sprouts, as even if the levels and ilvls are scaled to the same tier, a level 80 still has a lot more spells to pull their dps out.

I'm not sure if there's any workaround to this... maybe underleveled jobs get a buff when paired with overleveled ones, so the dps disparity wouldn't be too big.