What I mean with almost is when the error first occoured, that was the latest driver.
Also I just found out I was running a very outdated NVIDIA driver, will update it now (I was using 398.36 according to Geforce Experience)
EDIT: Good news, I updated to the last NVIDIA driver and the game seems to run fine now (not crash) BUT, looking at task manager to confirm this shows different, it seems as if the dGPU is just copying the rendered frames from the integrated graphics and just pushing it out. Screenshots below:
https://imgur.com/a/MJIL4Yv
EDIT 2: Taking a more indepth troubleshooting testing out various rendering modes, trying Comp. mode, with and w.o. fullscreen, gave me interesting results:
First with OGL Borderless gave me the same result, the gpu 1 is copying the gpu 0
Then swapped to Compatibility Mode with Borderless, still gave me same result, but with more stuttering. Finally on Compatibility mode with fullscreen, things start to happen (no crashes), first off, when playing gives the same result, HOWEVER, if I take on a replay, and alt+tab out of the game, the GPU will render in the background while the integrated do nothing, which is what I want! Another note is that after alt+tabbing it is almost impossible to get back ingame, if i click on the osu logo in my taskbar, it will only flash a black screen for a frame or so, but after aggroclicking it I came in, it seems like its random if you come in or not. However this is very inpractical and I would'nt bother using that mode just because of the 1 minutes wasted on trying to get on osu. Screenshot below:
https://imgur.com/a/AVqFEfu
EDIT 3: Found out the video decode thing, it was because instant replay was on by default, I turned it off and video decode is down to 0%. However the rendering is still parallel to my integrated gpu