Mmmmh, for me it's my toolbox, and I spend 7+ hours working with it. I just can't convince myself that gnome-shell is the solution to my problems.

To "work" on this issue, I decided to install it ahead of time, and try to change the session. To my surprise, it is fairly easy to do so !

GDM3 (the default login manager) looks into /usr/share/xsessions for possible "sessions" that can be started by a user. You can create your own, which I named "xsession.desktop":


The /etc/X11/Xsession script is provided by default on a fresh install. Basically, it will run shell scripts provided in /etc/X11/Xsession.d, based on the content of the file /etc/X11/Xsession.options. One of those option is "allow-user-xsession", which will make the Xsession script run "exec $HOME/.xsession" at the end, which works exactly like .xinitrc when you run "startx".

So in the end I just created 2 files:

• /usr/share/xsessions/xsession.desktop
  
• $HOME/.xsession
  

And I'm back to something I know ! There are still a bunch of thing I need to figure out how to do on Ubuntu (volume management, and the awful combination of "netplan" and "NetworkManager" for network connectivity as an example), but at least I can do so in an environment that I know.