@pipetboy It's already very possible by switching to mobile view emulation in the Dev tools within the browser. it's just that you have to every time you want to do that.
This is something I would love to have as well. One thing that would be nice is to have list of domains that auto open in an workspace. So when I open a link from an email, or another app it goes in the correct workspace.
If downloading anything is not working on Opera then, enabling
the storage permission may help you to get the file downloaded.
You can also try by clearing cache and disabling the extension
and then make a try.