it’s weird to me that these items are all just presented as problems to be solved, instead of justifying why this (often default, expected behavior) is a problem for progressive apps in particular.
I don't think highlight text when long pressing on UI elements is expected behavior for an app though. It would be for a website but can feel out of place in an installed app.
But I agree that UI elements (eg. buttons) should not be selectable. Even in regular websites, it's best to set the whole gamut of appropriate CSS properties so they behave like native UI widgets. I also make sure to set `cursor: pointer` on anything clickable.
Web apps that just set an onclick handler on a div and call it done are a pet peeve of mine.