That one was tricky to figure out for me, too. I had a colleague ready to give up on Emacs because of that very issue.

Myself, I also haven't thought about fixing `C-g`. I ended up settling on a compromise solution - I have `winum` package configured so that pressing `M-0` focuses minibuffer, if open, so closing defocused minibuffer is just `M-0 C-g` for me. The keys `M-1` through `M-9` focus the windows 1 through 9, as usual.

I use a config similar to this explicit one with sparse keymap: https://github.com/deb0ch/emacs-winum?tab=readme-ov-file#key...

As long as `winum-auto-assign-0-to-minibuffer` user option is `t`, which it is by default, `M-0` does what I described above.

Having a single key to "focus minibuffer" is also useful with recursive minibuffers, on which I rely increasingly often.