This has actually been studied. Turns out, zoomers are so reliant on smart technology like tablets and phones, they never actually learned anything about normal PC file systems or extensions. They literally don't understand what a folder is because they've never been exposed to PC or Mac environments.
I've seen people comment about needing to teach folder and file hierarchies to young people in CS classes because they grew up with cloud services and auto-save. Dunno how widespread that might be.
I've had to teach folders, file types and extensions to lots of ~18 yo. When I ask them where they saved a files they get confused and generally respond with something like "on the computer".
I am a sophomore computer science student and when I entered freshman year I was very surprised as well. Just last week, I was helping some kid with his intro C++ final and the entire semester, the guy has been saving everything to /downloads. He was wondering why every new program he made in Visual Studio failed to work. It kept messing up because he was in the same directory all the time messing about with the other 5 or so programs he made beforehand.
I'm reminded of that infamous game reviewer that couldn't figure out how to jump over a box on the first level of a tutorial. And then gave the game a bad review
By study, I don't mean in a lab setting, but more so the data has been collected by employers reporting that their Gen Z staff is technologically stunted.