the last thing that could be wrong is a screw is not fully tight, if anything its too tight!
I want to believe you that this is the right fan and I am sure you believe it is yourself,
but dude please understand although admittingly I am not specifically incredibly experienced with dissembling GPUs - this is not my first time playing with hardware, I own a bricks and mortar computer repair shop that specializes in laptop repair, ive been doing this professionally for 16 years - there is not really that much to these things your looking at less than 20 screws and only 2-4 different screw types depending on the model, youve got the shroud, the fan the pcb board with the gpu and vr,
it goes like this
1) remove all screws
2) remove back plate
3) remove gpu compression plate + more screws depending on model
4) gently pry apart
5) take screws off fan
6) screw fan into shroud, plug into board
7) clean off old thermalpaste and apply new
and believe me here I WANT TO BE WRONG but I just dont see what I am missing, maybe someone else here who has specific experience replacing gpu fans could tell me what im doing wrong, im thinking maybe if I had some kind of spacer or something ? I dunno - I just want to put my gpu back together!