How to make Ubuntu 18.04 to auto login into i3

Question

I want to have my Ubuntu 18.04.1 system autologin into i3, but all attempts were failures and gdm keeps booting into gnome :( Things I've tried:

1. I've created .xinitrc that launched i3 (it worked with startx command, but wasn't a default variant for gdm)
2. Made a symlink to .xsession ln -s .xinitrc .xsession

3. Added ~/.dmrc file with

   [Desktop]

   Session=i3

4. Wrote DefaultSession=i3 line into [daemon] section of /etc/gdm3/custom.conf

5. I tried doing alternatives with update-alternatives --install /usr/bin/x-session-manager x-session-manager /usr/share/xsessions/i3.desktop 48 and then update-alternatives --config x-session-manager with selection of that entry
6. Tried update-alternatives --config x-window-manager and set i3

None of that helped, what am I doing wrong?