I have a PC with Oracle linux 5.8 64-bit. I upgraded to 5.9, and alles in Ordnung.
Then I upgraded to 5.10 and first boot, get the error can't start X server.
So you have to try configuring (with blurry screen at wrong resolution), logout at least twice until you get it working.
Otherwise, changing the graphics card may solve the problem.
Now this PC has a Radeon X300 graphics card. I use such old stuff, as RHEL is a bit old and may not embrace the latest GPUs.
I do not need a high-power gaming card for my purposes.
Also I have an application which has problem with Nvidia graphics cards.
Anyway after some trial and error, I discovered that if you choose the radeon_tp driver, then X server starts okay and comes up correct resolution.