I loooove my steam controller for first-person games. The right track pad for camera controls just clicks with me. I guess it's because I'm a PC gamer first and foremost, so I'm used to mouse-like aiming rather than the analog-style stick aiming.
I never really used the left track pad though...
That being said, I was let down by the steam deck trackpads. Maybe I just have big hands, but I could never use the right track pad the same way I do with the steam controller.
Also a general comment: AA/AAA is the best if you get some rechargable batteries. No waiting for charging when something is out of juice! Plus you can just get a new set of batteries if they ever die instead of a whole new controller
I think some of it comes down to what your brain is used to.
I usually use mouse/keyboard, that kind of constant movement from holding the stick in a certain position is kind of foreign to me. Whereas having the right track pad basically emulating a trackpall mouse instantly felt really natural. In this case it's like a mouse in that your movement directly translates to camera movement.
You may just be more used to analog sticks