I just had the same experience, except I'm running macOS 10.14 Mojave.
- Updated from driver version 6.3.37-3 to 6.3.38-3 - straight away my pointer became juddery and jerky, jagged and flickery, severe reduction in fps, lack of precision, totally unusable
- Downgraded driver back to 6.3.37-3 - pointer movement was smooth again, normality was restored.
This was a rather traumatic experience, and reminds me of how dependent I am on Wacom as an ex-RSI sufferer. I use a pen & tablet as my regular pointing device. Have been for 20 years, and cannot work without it. So having something like this happen is like having my right arm cut off.
I don't think this has anything do with macOS 10.15 Catalina - I'm not running Catalina. I'm still on 10.14 Mojave. All I did was driver upgrade the driver and then downgrade it again.
A question for Wacom: what changed
between driver 6.3.37-3 and driver 6.3.38-3? Whatever it was, the culprit seems to involve driver version, not macOS version.