Hi,
I'm running macOS 10.15.5, Logic 10.5 and MainStage 3.4.4 with the current versions of KeyLab mkII, AnalogLab 4 and the V-Collection with a Scarlett 6i8 3rd generation.
I have NO issues!
Before I upgraded end of 2019 I made sure that all components (and also other plugins...) are supporting macOS 10.15 - I think that was the most important step in the beginning of 10.15.
HTH
Alexander