Question / Help Scaling causes pixelated overlays

So I made a new overlay recently and I saw that the overlay was HIGHLY pixelated. Taking into consideration I fixed the overlays resolution and nothing happened.
Next I went ENABLED hardware acceleration in Chrome again and the picture was slightly better (Firefox was ok Opera was not). Next i tried not scaling the stream down from 1080 to 720. So streaming on 1080 was ok I think but streaming 1080 on a single pc even 30 fps was not stable. So whats wrong then that a 1080p overlay gets pixelated on stream but it looks fine on OBS or in an image viewer. I tried 264 encoding and NVENC hardware encoding aswell and on both sides it looks bad.

Link to a clip where i use 264 encoding:

970 gtx
16gb ram

Keep in mind that my pc has severe issues with windows 10 and i have a new problem popping up every week.
I have NO CLUE what could cause these kinds of problems and I really want to fix it.
All latest logs are included (Note i used NVENC on the last couple of tries i have been using 264 encoding but for some games it just doesn't cut it ).
Ty for any suggestions in advance.