My 3090 FTW3 Ultra runs around 70C on the OC VBIOS (more aggressive fans).
However, my case is massive and has tons of fans sucking in cool air - including two 180mm fans on the side of the case blowing cool air right onto the GPU.
I suggest, again, removing the side of your case to see if that improves your GPU temperature. If it does, your case needs more airflow. I go for positive pressure since it's easy, but that's just me and I don't mind dusting.