Oof, what keys do you normally use? I use the numpad and surrounding area and it's proper annoying when games dont have full rebind support. Even have the numpad enter remapped to space in windows (some games still recognise it as numpad enter though) as it is a common offender
I have jump bound to the left arrow key (not the numpad one) and it works for some jumps but not all. So you end up using left arrow for some jumps, space for others and this is a pain when you have to shift between both. It's the same with the crouch key not being 100% bound to the keypad enter. One skill you can get is soft landing, you apparently press crouch just before landing to decrease fall damage. Of course it won't work if you rebind crouch.
There are also a number of skills that require the use of keys such as V, Caps Lock and Left Shift. For example run is a skill you need to learn (cus that's like real life) and uses the left Shift key only. Yeah, good luck getting to those easily in a battle or when parkouring. I now have a bunch of unspent "skills" because the ones I can pick are utterly contrived and useless to access or use.
In the end these issues rendered the melee combat boring and contrived, so I just put the difficulty to easy and button smash.