The display wouldn't be the issue, but the GPU might be. You haven't told us which that is though.
inxi -GSaz --vs would if it was a recent inxi version. The inxi provided in 18.04 os a broken antique. If you wished you could get the latest directly from upstream
here. If you do, you should purge the installed version.
Code:
lspci -nnk | grep -A3 VGA
can provide some of the GPU info. It would have helped if you had collected some logs from the 20.04 installation try, such as /var/log/Xorg.0.log in particular.
Since Ubuntu is a derivative of Debian, you might give installation of a recent Debian a try. 12.5 is current, but 11.x is still supported. 20.04 support will only continue for about 12 more months.