I totally agree that, yes, there are no silver bullets. But regarding UI, modern web browsers come quite close in my opinion. And you can avoid lots of system administration work, especially when you have a large number of users.

Didn't look into it for some time, but there are multiple approaches to handle this transparently.

• The File System Access API: simplifying access to local files
• Building an App that uses a Web browser internally. Using something like Flutter, you can probably compile it for Windows and Linux. This would still minimize doing a lot of OS specific stuff, but would give your the ability to add custom JS interfaces for things like file access. Since most of the logic is delivered from the webserver, you hardly ever need to update the local app.

Of course, you could just bundle the Perl application and all required tools into a docker container and run it on the users computer. And still use the webbrowser as the UI, letting the boffins as Google figure out how the users OS does multimedia.