Nuendo 12.0.30 GUI lag

I am experiencing quite terrible slowdowns and GUI lag in 12.0.30 (especially when trying to scroll or zoom in the project and using middle mouse click). N12 also seems to freeze for a while when opening two instances of soothe2 for example.

Neither of these things happen when I open the same problematic project in N11.0.41 though. I have tried using older versions of N12 but to no avail.

PC Specs:
CPU: AMD R7 3700x
GPU: AMD RX6600
64gb RAM
Windows 10 (running all the latest drivers and updates etc.)