Idk if it's cannon, since everybody explains Izanagi differently. But in this FF the take will be, that Izanagi functions as someone casts a genjutsu on one self and for a certain period of time, they can switch reality and genjutsu, meaning that reality becomes a fictional genjutsu and the fictional genjutsu becomes reality.
So the MC who is a reincarnator will use this reality bending to his liking and will abuse completely.
He is an Uchiha, but will kill every clan member with a functional sharingan, he will then capture the children and let them grow, so he can get more sharingan. With this he will use Izanagi to give himself every bloodline, every dojutsu, his own dojutsu, every kekkai genkai/tota/mora etc. He will become stronger than Kaguya or Judara, in terms of pure power (not skill), in literally minutes. He will simply cast a genjutsu on himself, where he has a bloodline that contains any bloodline on the planet but a perfected version where the different abilities enhances themselves and aren't straining on his body.
Etc.
Just an idea to abuse Izanagi to the limit, since its basically time limited reality warping in my opinion, but that time limit can be negated, with multiple sharing and.