If you're running GNU/Linux, chances are you'll have hundreds, if not thousands, of pieces of software that run totally unsandboxed.
Yes, a very small minority of applications are unfortunately primarily distributed via flatpak or snap, and the distributors don't care about the user experience, so it's error-ridden and problem-ridden, but chances are you can get a "normal computer program" version of it unencumbered by such grossness.