Then perhaps you could change your bootloader video settings and see if it helps, check your monitor specs, etc.
Note that besides the console resolution setting you may have a video=NNNNxNNNN entry in kernel options. The problematic box has this, set to the TV resolution, and another, connected to the monitor, don’t. I haven’t played with it yet, first I have to find what part of the myriad video modes during boot it affects.
Perhaps you could go the other way I did - if you have access to a TV that you can connect to your box, of course.
Well I cannot explain what happened originally when I updated, or when I installed a second copy of TW. I then managed to screw up trying to use BTRFS snapshots. So I bit the bullet and re-installed TW on the original disk and it’s now the only one installed and it’s working fine, no problems with the graphics card or monitor, never was a monitor issue as I have KVM switch so I can see my W7 desktop on a mini PC which runs my weather station so I know the monitor is good.
Something happened on that last update which screwed it but no ideas what.