as a first guess this sounds like intel gpu problem, have you tried any of the fixes?
1 - determine which driver your using grep -P “(L|Unl)oading” /var/log/Xorg.0.log the one that is not unloaded is the one in use.
2 - fixes to try - if your not using modesetting try that, otherwise look up uxa vs sna issue and specify in 20-intel.conf
No up to you but you the default is to chack for updates at log in or some fixed period. In any case this will not stop startup. It is something else causing the problem. Since you had the same issue on Ubuntu I’d look at your hardware, Video card maybe??