Addendum to 1: While QMK is nice, I personally prefer ZMK and use it even on my wired boards. So just wanna say, “forced to use” sounds a bit harsh. ZMK is a great and very capable firmware, and it does certain things better than QMK.
tbh it sounds like what you need is better firmware configuration if these things are out of reach. a common approach is to make the spacebar a tap-hold key that outputs space on tap and switches to another layer on hold. on that layer you could bind arrow keys on ijkl, for example, and still have shift, alt, ctrl in easy reach.