New install boots into black screen with underscore in the top left of the screen

This maybe your issue

e class='quote' data-post="1" data-topic="71674">
It is looking like the new Mesa update is causing problems mostly with nVidia systems…refer to: So far there have been reports with nVidia systems (including hybrid systems) & Tigerlake Intel being affected. I would recommend upgrading with caution. So far, Gnome & KDE have been affected. Asking everyone to post: lspci | grep 'VGA' or inxi -G Or both. Thank You!