Apple's apps bypass firewalls like LittleSnitch and LuLu on macOS Big Sur

Both major consumer OS vendors seem hell-bent on bringing the OS layer under their complete control. As a power user, it's very frustrating. Meanwhile "desktop" Linux still kind of sucks, just like it did 10 years ago. I don't have much hope of seeing a compelling, unified UX out of Linux in my lifetime.

Curious, what sort of things make desktop Linux suck in your opinion? I’ve been on Linux for years as my primary machine and haven’t encountered anything that made me switch back.

Can you select a file in the whatever is the Linux desktop equivalent of Finder and hit the spacebar to get a quick look at the file native to the OS?

Can I run the software I need to be able to make a living?

Can I run multiple HiDPI displays that I can connect/disconnect as needed without causing issues?

I honestly don't know if these are or are not available features. The first question is a muscle memory thing for me and makes me thing Windows Explorer is broken. I know the second question is not possible, so after that it's full stop. Question 3 is something I anecdotally know that has been an issue in the past, but would be problem for me if it is not possible.