One thing I found, coming from multi-monitor macOS to Kubuntu, was having to adjust to both desktops sliding left/right at the same time. I still don't really like how it effectively shuts off applications that aren't on the active desktop, and kinda puts a barrier between work spaces.

With a Mac, I have a regular desktop on one screen, with full screen applications on the other, which I can swipe between as much as I like. I miss not being able to do that in Linux.