I think it would be nice to have a feature similar to Ente Photos for Guest View. The proton user selects the images they want to share and those are the only images that can be scrolled through or seen for the user holding the phone. They can exit guest view by using the fingerprint or pin that is setup. It is similar to iOS guided access. Since I am on Android I would love something like this so I can only share what I want with people I work with when I hand over my phone.