Custom Resolution Utility (CRU)

[Urby66]

I try to read back several pages, but unfortunately I'm not able to see solution to my problem.
So my case is the following:
I have a Samsung Freesync capable 4K TV (QE55Q70RA) I use it with RX5700XT video card via HDMI cable. So the TV can support 60Hz Freesync in 4K and 120Hz Freesync in 1440p. The problem is the resolution of the TV remains in native 4K resolution doesn't matter what resolution I change in windows display properties. (like GPU scaling on, but I double check it, and it is off)
Some games behaves the same when I set the resolution ingame to 1440p (seems GPU scaling on, native monitor 4K resolution remains).
Same games change resolution but changes to 1440p 60Hz only.
When I force 1440p 120Hz from desktop with Qres, the resolution can change on desktop. After starting the game is is jumping back to 1440p 60Hz
The detailed resolutions field in CRU shows 2 record for me, the 4K 60 Hz, and the 1440p 60Hz. When I change it to 120Hz and restart everything remains the same.
The graphics drivers, the Win 10 home, and the TV firmware are up to date. The HDMI cable also seems ok, because I can force the 120Hz with Qres.
So the question would be, how can I force the display scaling instead of this GPU scaling behavior?
How can I force the 1440p 120Hz ingame?

Thanks for the support!