Not what you asked for, but you may be interested in getting a keyboard running QMK where you can define these kind of modifier overloading (and much much more) on the keyboard itself, so it's "portable" and doesn't require OS/DE settings
I switched because of neovim, and got used to it. I was never the kind of guy to press caps to type capitals, always just kept shift pressed down with my pinky, so i basically never used the caps key anyway
I like the backspace there like Colemak has. I can do Fn-Backspace(capslock) to activate Caps Lock but that's something I added to my Keyboard separately.
I use keyd for software remapping now, and I like it a lot more than xkb's esoteric options. It has functionality for layers like layer:C, where any "passthrough" input will have the defined modifier (or combo like C-S-M), but you can define whatever other bindings inside.
Long story short, I've used it to remap caps, control, shift (with a custom shift layer for some symbols), and meta, with overloads, double tap/hold into layers, oneshots, timeouts, and all sorts of (surprisingly fluid) nonsense. It's so much easier than wading through xkb options for me.
To sidestep the question slightly less, I always got rid of capslock altogether instead of swapping. That still leaves true escape to be hit accidentally, but I think there should be an option to change escape too?
Edit: what I always used was
# make CapsLock behave like Ctrl:
setxkbmap -option ctrl:nocaps
# make short-pressed Ctrl behave like Escape:
xcape -e 'Control_L=Escape'