Samsung 49" S95UC frame skipping?

[creon]

Hey everyone,

I am really desperate at this point because I have no idea where else to go to.
I just received my S95UC yesterday, having tried everything I could but I noticed pretty early that something's off, coming from having a 144hz XL2411Z as a second monitor for years now. So I'd say I know how 144hz feel like.
When firstly connecting it to my GTX 970, I quickly came to conclusion that my 970 only supports DP1.2, which would not be enough for the monitors 5120 x 1440 px at 120Hz.
So I went out and quickly got my hands on a RTX 2070 Super and installed it. Did a fresh driver install with DDU and tried my luck again. At this point I had also ordered a new DP cable, as I was unsure of what type of DP cable I had (I tried with the shipped HDMI cable, my own HDMI cables and one of my own DP cables before) so I ordered a new "16K" DP cable as well. Today it arrived, so all my hope was on it.
But.. as sometimes it goes, I did not have any luck. The Samsung live chat support couldn't help me at all, only offered me to call back some time next week, so I am currently really about to get crazy over this monitor, send it back and order a LG UltraWide 49WQ95X-W instead. (Does anyone have any insight on this one by the way?)

These are pictures of the frame skipping test, when running the monitor on 60Hz I get straight lines, but whenever I put it on 120 (doesn't matter which resolution, I can't get straight lines on even the lowest possible resolutions) it seems to skip every second rectangle..

What else can I do in this case? As it didn't work on neither of my GPUs I am really devastated at this point

Thanks in advance for your replies and help