I'm assuming my issue is Off Topic as LibreELEC (nightly) works brilliantly on my Rock64 
If it's deemed inappropriate, feel free to close/delete this thread.
I have 2 Rock64 devices, both connected via HDMI cable to my AVR (Pioneer SC-1224) which in turn is connected via HDMI cable to my 4k LG TV.
One Rock64 runs LE and it correctly identifies my AVR (as seen in Settings - System - Audio) and in Setting - System - Display, Resolution is 3840x2160p, Refresh rate is 60.00 and GUI resolution limit is 1080. If I remove the 'quiet' keyword from the kernel command line, I see that all the boot messages are nicely lined up.
Another Rock64 runs Debian Testing/Bookworm and when using a Debian/stock kernel, then the left (8?) chars of the boot messages aren't visible. When starting a GUI, I'm still missing the left part. So I build a patched Debian (5.15) kernel which consists of patches taken from https://github.com/LibreELEC/Libr…s/linux/default. When I use that to boot up, all the boot messages are properly lined up, just like with LE 
When I then start a GUI (I've mostly tested it with sway (wayland), but also tried it with Xorg) all is well as well ... in 4k resolution. But the Rock64 doesn't have the (memory?) bandwidth to properly support that resolution and I also don't need it; 1080p is absolutely fine (for f.e. ncmpc). But when I switch resolution to 1080p, the output is shifted again. Think of like holding a piece of paper over the screen and then move it up and to the left, so I'm missing a part of the display output both on the left and the top.
Switching to any other resolution causes the output to stop entirely.
I'm assuming this is an upstream bug, which I'd like to report, but I have no idea in which component the bug is and therefor I don't know which upstream to contact.
As you do have it working and with your patches I already made an improvement, I'm hoping you can tell me where (most likely) the bug is located.
Thanks in advance and sorry if this is/was inappropriate.