minecraft 1.8 to 1.15 always crashes when loading a new world or joining a server

Every time i start a new world in 1.8 to 1.15 versions (and subversions, i.e. 1.8.9), my game freezes and i have to force quit it. i have no idea why this is happening, but it happens every time no matter what i do. also when it comes to 1.15, it won't even load into the main menu. the red bar just never completes.