So my first idea is a systemless MC that is transmigrated into the Naruto world at any time. And the MC is a super genius in tech or has some kind of science ability like inspired inventor. They abandon chakra for a super powerful robotic body as well to deal with the Otsotsuki.
The storyline involves the MC having intergalactic technology spreading his machines across the galaxy and many worlds. Eventually he encounters the Otsotsuki and viewing them and their world trees as parasites to all life starts a galactic war against the Otsotsuki.
It's interesting because the Otsotsuki travel with dimensional portals while the MC travels through space. And he abandons the path of chakra to wholly counter the Otsotsuki the masters of chakra who aren't immune to his weapons that are technically taijutsu like star breaker engines and black holes.
So we get the explore the entirety of the Otsotsuki clan and their true might. And you don't have to worry about being so OP that the ninja world is irrelevant because against the entire Otsotsuki it already is.