Cant enable 240hz on 4k monitor

Hello,

I have a 4k 240hz monitor with Freesync Premium Pro.

But I cant enable more the 60hz using a the Dp Port that came with the monitor.

I can enable 120 in settings but when I do, the picture starts to blink.

Everything is up to date. I use amd CPU and amd GPU.

Tried changing from Gnome to KDE and Hyprland. But none seems to work.

I have no problem to activate 240 in Windows 11 tho

Do anyone else been having these problem?

Thankful for any kind of tips and tricks.

Cheers