Choices and self-inserting have little to do with each other, actually. You can set a story with no personality self-insert on rails without much trouble (best examples are probably those gachas like housamo and anados) or you can make fleshed out mc and give him meaningful choices (password, burrows, lust shards) (yes, Cody is kind of self-insert, because he's like regular horny internet user, but that's personality too).