Keyboard movement issues.

Hi All. Wonder if any of you guys can help. I'm at my whit's end with an issue I've been experiencing ever since I upgraded to a RTX 5080. Since the upgrade from a 3080ti my character keeps moving and doesn't register me lifting my finger off the keys- it's like it's constantly moving and is starting to get annoying. I thought it was my keyboard but I've tried everything- swapping to different keyboards, USB cables, plugging directly into the red USB ports in the rear of the pc, reinstalling my gpu drivers literally everything apart from switching back to the 3080ti. I've noticed it's happening on Halo Campaign evolved but not as much. Any ideas on what to do?
PC specs:
Intel 14700k
GPU 5080
PSU Corsair RM 1000e
32gb Ram
2GB WD NVME SSD