"lock" doesn't work for me in the game, I reinstalled the game and checked the integrity of the files, but "lock" still doesn't work, maybe there's a way to just change bind?
I'm not aware of any way of changing the bind. If you are playing with kb&m, you need to be aiming on top of an enemy to be able to lock on to them, so perhaps you are not doing that.
Lock-on is only really useful in certain situations and largely just slows people down or leads them to silly mistakes, so if you wish to improve at the game, I would recommend starting off by not using it anyway.
In-game settings allow for movement/restart buttons remaps only. If you feel really uncomfortable with scroll you can try using autohotkey but I have no idea if it's going to cooperate with the game (with hm2 it doesn't)
(edit: yeah as expected AHK scripts don't work for hm1 either)