I'm running Fedora 33 on my new NUC6i7KYK Skull Canyon NUC, a long-overdue upgrade from my old 3217UDC3217BY.
When I hook it up to my LG OLED 55C8PUA 4K TV, as soon as we get past the scrolling console messages, I just see an "Invalid format" message shown on the TV. Nothing else from the NUC. So this would suggest that the NUC is trying to use a graphics resolution that the TV does not support; but it's configured for 1920 x 1080, so should not be a problem.
I've tried changing configs on the TV side, to set different aspect ratios, and also setting "Just scan" to "on" and "off" (the default is "auto"). No luck.
I've also tried different HDMI cables.
Also upgraded the BIOS to latest.
But here's a clue: if I boot Fedora into "Rescue mode", Gnome login and desktop all works without issue.
Any thoughts appreciated!
If you have a working monitor around, you can use it temporarily to set up a WebRTC session. Make sure you're using Wayland and Firefox. After screen sharing starts, you can enter the room link on another device (like your phone), disconnect the monitor, connect the TV, and change the resolution in GNOME Settings.
Your " get past the scrolling console messages" suggests that the machine is booting properly, but switching to graphics mode fails.
I do not have any experience with Fedora, but in general on Linux you can switch to a text mode console with Ctrl-Alt-F1 (or F2..F6).
If that works you can check /var/log/Xorg.0.log , dmesg , . . .
If it's not possible to login in text mode, because it does not get that far, then a serial console might work: https://roll.urown.net/server/serial-console.html