Also it is hilariously difficult to decline a call on Google dialer.

It’s as simple as swiping down on the screen. I agree it’s a little under-sensitive if you try to swipe down from the circle with the icon at the bottom. But you can swipe down from anywhere on the screen and it will decline the call.

Sounds like you had a corrupt installation.

Flatpaks can also be used to run CLI programs, but it requires using flatpak run instead of using the apps standard CLI command. But you can create an alias and should work mostly the same way.

For example, I have neovim on my Debian laptop via flatpak. So in order to run it, you have to do

flatpak run io.neovim.nvim

You can create an alias for that command

alias nvim='flatpak run io.neovim.nvim'

And then you can use the nvim command as normal