Funny thing just happened. After about a total time of 10 hours spent foraging the forum and trouble shooting over the past days and finally turning to a forum post myself. I tried one more thing for the shits and giggles. I thought hmmm the problem lies with the graphic rendering in some shape or form for some reason. I have fixed it! I turned off frame generation for GTA V via the NVDIA App and now it finally works.
RPH can´t deal with it. It would be Interesting to see if other users with modern hardware (I think RTX 40+ Series right?) can reproduce it. If so might be worth adding to known Issues.
TBH dont really need framegen for this game with that card, I just have it on by default for most games cause its nice.