I have an ASUS G751JY laptop.
I can boot and switch between consoles with CTRL-ALT-Fn no problems.
I can start X Windows no problems with either of the current branches be it short or long lived version ; however once X is loaded I can not switch to a console - the windows is completely blank - it doesn’t even look like the back light is on, I can switch back to X using CTRL-ALT-F7 no problems and everything there is working fine.
When I exit X Windows I have the same problem, no cursor, no screen output and it looks like no back light, the console however is fully active and I can type in reboot to have the system shut down and restart or i can type startx and have the system run X windows again.
I am confident with Linux but am not an “expert” - if there are any logs you would like to see please let me know but from what I can see of the X-Windows log everything seems to exit cleanly.