If you were to mix Izuku's personality with another MC or character, be it for a crossover or idk, who would you like it to be.

The thing about Crossovers or making Izuku different is that you should still make him Izuku, not just a character with his face and hair, so the way I've liked the most of that is making him a composite character. Keeping Izuku's core traits is not that hard. He still needs to be heroic to the bone, like not helping someone will make his heart stop, he doesn't need to be shy (especially if he's strong from the start) but it should still be present. The notebooks are not something I consider like core but they can be added, making it some way to store things to remember rather than be some god-tier analysis that will do everything.

Anyways to answer my own question, the character I want to mix Izuku with is Sakaki Yuuya from Yugioh Arc V, because seeing Izuku as some kind of clown Twink/Twunk entertaining people sounds fun asf.