Adding kernel commandline options?

As a simple test you can press ‘e’ when the grub menu appears on boot, then go to the line that mentions rhgb quiet and add the video=[...] text after that. Then you can press F10 to continue booting.

If it works and you want to make it permanent, then you can place it in the file /etc/default/grub on the line that says GRUB_CMDLINE_LINUX. E.g.:

GRUB_CMDLINE_LINUX="rhgb quiet video=DP-1:4112x2572@120"

Regenerate the grub config:

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg

and reboot.

If you want you can also add fallback resolutions to the parameter, e.g.:

video=DP-1:4112x2572@120,1024x768

or 

video=DP-1:4112x2572@120,auto
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