don't know why people are obsessing with the partition scheme interest of two apps using as much of a windows10 installation.

my full / for a desktop debian with ton of stuff is under 4gb.

That was what was insane to me. I expected a couple hundred mb each for my first couple of apps. Not a pleasure in itself, but I was blindsided by the 10gb. The apps were clearly also part of the problem - they should not have so many dependencies. However even after I removed them, flatpak was using 8gb+, I had to purge it to reclaim space. That is why I called it a hot mess.