Have you tried enabling Force 422 colour sampling and rebooted?
I can’t recall this, but I will try it, thanks!
You’ve changed these settings from their default values at settings->System->Display. Could you first try with the default settings? At the bottom of the menu you can reset them. A reboot will be required, I think.
Please re-read the paragraph Providing diagnostic logs in this How to submit a useful support request
You need to turn on debug logs then please reset your display settings as @JimKnopf says to their default, set your resolution to 1080p60, re-boot and upload the logs.
Thanks for everyone helping me! I have reverted everything back to defaults, rebooted, set 422 color subsampling and after this, setting 60Hz works perfectly!
Don’t know what change made it working, but it works.
Thanks again!