Can you do that with Windows or MacOS?
Yes, I can in fact download programs that aren’t on the Windows or Mac app stores. Are you even paying attention here?
But you can’t completely switch your system with a different version managed by different people while preserving your home folder.
You can’t choose the windows you get, Microsoft chooses for you
I’m sorry, are we talking about shit that users do or are we talking about masturbatory sysadmin jizzcup filler? Because it seems like you’re not paying attention to the conversation, which is that Ubuntu doesn’t even let users install .deb packages through the fucking package manager.