While the game runs when in 3D view it's very laggy and stutters quite a lot making it almost unplayable. I tried modding it with the V3.3 Upgrade mod but unfortunately that suffers the same. Any ideas on how to make the game play more smooth?

Update: Found the issue, it was caused by the mouse cursor, I have seen similar issues with other games, think it was caused by 2020 Nvidia driver update.
Fix: Updating to the latest Nvidia driver has now fixed the issue.

Thanks for pointing this out. I experienced lag with a previous nvidia driver and had to roll back but I'm glad it's fixed in the new drivers.

Just wanted to confirm that updating NVIDIA drivers is very likely the solution for anyone else who has this problem. Just tried it myself and it fixed the strange lag and cursor flickering.

Thanks for posting this update and fix! I had the same problem and the fix worked perfectly!