Catalina was the primary motivator to move back to Linux for myself, and I don't regret it. If you care about things like this, you can configure Plasma Desktop with macOS features and shortcuts and end up feeling right at home.
Currently have my work desktop (linux + windows for gaming :D) at home for lockdown and a file share/media server (linux) hooked up to the tele. All seems to work. Even my firewire audio interface is more stable on my linux work desktop (it's not supported on Windows 10 > 1903 / OSX > 10.13).
The one thing that is keeping me switching is Apple Music w/ the iCloud Music Library syncing. Legit the only reason I haven't ditched my 10 year old macbook pro yet.
The tl;dr is to use Plasma Desktop, take advantage of its ability to create keyboard shortcuts for everything, and use Plasmoids to create a global menu and dock.
I didn't mention it in the post, but KDE Connect[2] works on most desktop environments and integrates with tablets, phones and other computers, and it's great.
There's sandbox info in the parent post[3], if you need a sandboxd replacement, too.
[1] https://news.ycombinator.com/item?id=23473207