Clover resolution stuck at 720p after switching from HDMI to DP

Due to problems with a black screen after turning it off and on again a user suggested to switch from HDMI to a DP cable.

The problem with the black screen is vanished. But now the clover boot screen is in 720p max. Prior it was in 4K.

I tried switching clover display settings and disabling CSM in bios, but nothing helped.

Anyone some tips on this? Thank you.