I'm trying to install Xubuntu in dual boot on an Asus Zenbook 14 UX431FN.

I got the Live USB version to run only in sage graphics mode. It started automatically a files check but then I could press ESC and the graphic server started. I've installed Xubuntu and everything seemed working fine.

However, now the safe graphics mode doesn't work anymore.
If I choose "Ubuntu" I only have a dark screen.

I've tried the following solutions:
- advanced options → recovery mode. It only shows me a menu where I updated/upgraded everything, but I can't start the GUI
- I booted with
nomodeset noacpi acpi=off
, but it doesn't work either. It stops with a dark screen and the cursor in the top left corner. However, in this case all the other shells work perfectly (Ctrl-Alt-F_).
- I followed the advice in this post: https://ubuntuforums.org/showthread.php?t=2420705 installing manually the binary file for 1920x1080. But it didn't work, same results.

I guess the problem is the Nvidia graphif card MX150.
I installed nvidia-drivers-440 as suggested, but with no results.

What can I do?