One could filter much of the crapology somewhere safe, and then have a relatively tidy local browsing experience.
I'm too busy to take this idea past the handwaving stage, but it seems like someone should have already done the homework.
https://megous.com/dl/tmp/8eaa15e187fa9a2e.png (ff1 being the user)
I trust it more than browser's internal isolation solutions, like tab containers, which I like to use for other things, like testing web apps using different login sessions at once.
I'd hate a remote solution. ;) Though this is not for privacy but more for protection and better low effort isolation.
Does drag and drop work between windows owned by different users?
It doesn't seem like it would do much against a device compromise.
Indeed. https://www.mightyapp.com/
For trusted sites (ones the user logged into), this could be disabled.