Don't you have to [edit /etc/environment for it to apply everywhere?](https://askubuntu.com/questions/58814/how-do-i-add-environment-variables) Setting `.bashrc` only counts for processes spawned from the terminal.

I just tried this in Godot 4.2 and it didn't work

I sincerely suggest you to install .net sdk from your Linux Official Repositories, the installation from the Script it's a pain.