After upgrading my regular workstation I upgraded my Precision 5540 laptop to Qubes 4.2.0 too. The install went perfectly smoothly, no problems whatsoever. And even now it seems to work at least as well as 4.1.2.
I’ve been using the system for about a day, haven’t noticed anything broken - video (1920x1080) works fine, do does audio, etc. The one thing that might not be great is power management - the fans seem to be noisier and battery life weaker than e.g. on Ubuntu. But the laptop is ~3y old, which may impact battery life, and I use it exclusively with Qubes so hard to compare noise/battery life with other systems.
I’m not sure about suspend/resume - sometimes it’s as if the laptop had problems entering the sleep, and the fans keep running for a while. But I never had problems with wakeup from sleep.