I recommend the upgrade. I can't imagine any performance hit. However, you may want to check that all the software you want to use/continue using is fully compatible.
Another good reason to stay up to date is important security fixes.
You are strongly encouraged to contact HyperDock developer directly about Catalina compatibility.
It is unwise to trust the participants of an anonymous Q&A forum like MacRumors for such information, especially if this is a critical application for you despite its relative obscurity.
please explain what you mean by, "problems with the video."I've got a 2018 with 16g of memory. I upgraded to Catalina .2 and had nothing but problems with the video, reverted back to Mojave and haven't had a single issue. I may try it again with .3, but for now not even going to look at Catalina. Love my air and the portability.