Not sure what you’re thinking of was done in a previous mod. You can play the game without masteries/classes, but that means you’re relying on skills from items in the game. This is something already in the game and has been since 2019. If you do it on hardcore through to Ultimate Forgotten Gods content there’s even a reward for doing it.
This is the thread about it
and this was the first build to do it solo self found.
