Just a note that there's a whole app called rcmd for switching apps using the Right Command key: https://lowtechguys.com/rcmd

I'm the developer and have the same exact use case: viewing one window at a time on a single space, instantly switching between them.

I used to map those hotkeys manually using Karabiner, skhd or BTT before, but I figured a semi-dynamic tool might fit this better.

Another thing that's useful for me is using yabai (https://github.com/koekeishiya/yabai) with its Stack layout, which automatically maximizes any window (with or without padding if you want)

Basically:

    brew install yabai

Then add this in ~/.yabairc

    yabai -m config layout        stack

Then start yabai and add it to launch automatically at login:

    brew services start yabai