I think I’ve read that negatives and hangs just make you better at negatives and hangs, but that it doesn’t carry over much to chin-ups and pull-ups.
I’ve gotten good results from a machine in my gym that provides assistance for chin-ups, pull-ups, and dips. I made rapid progress and now can do 10 body weight pull-ups and dips with added weight.
If you don’t have access to a machine like that it is pretty common to use bands to provide assistance, either looping them over the bar or stretching them across a squat rack.
By using assistance you can do the proper movement and not worry about whether the effects carry over.