4k in menu leads to lags in playback

when i set 1080p as interface resolution, i can play all files (or streams) without problems. But when i switch that to 4k i have timing problems. When i watch IPTV, its like as if 2-3 seconds are at 80% speed and then at 120% speed.
I have this 1080p resolution now since a couple of month but it feels very wrong to me.
Also, the menu is not fully visible. E.g. the clock display in the upper right is partially missing because of the 1080p resolution and then 4k in playback.

Is there anything i can do to have a 4k resolution in the menu and then 4k resolution also when i play something?