I also have the same screen flicker. I have a HP Laptop with AMD graphics. If it helps at all I can post the model number later. I was trying to troubleshoot.
Currently I'm loving Zorin. I've tried out LinuxFX,Ubuntu Mate,and BionicPup before but do to some confusion defaulted back to Windows. But I legit love Zorin and my Linux understanding over the past few days has grown exponentially.
I did a search on this issue, since I am not sure on this, either.
I found this:
One of the suggestions is a Temporary Fix... I think it would be worthwhile for you to test that. If it works, then that will establish that it is the graphics or drivers, not the hardware.
I installed Zorin 16 Lite on my Lenovo Ideapad today. Screen flicker comes and goes. My screen flickers about 3 times/sec when it happens. I ran the commands from here, but that did not fix it. I have an AMD Stoney GPU.
It supposedly was fixed by kernel 5.3 / 5.4 - Zorin OS is currently using 5.11.
Not sure if it regressed or if the fix from the previous kernel did not work.
Too bad it is not a fix, though.
I can't decide which I love more... Nvidia which just outright says "no" to open source or AMD which pretends to support Open source while simultaneously utterly ignoring it.