I have been researching QR code generators. What I have been looking for is a bit "anti Proton philosophy", but this is exactly why this might be an idea for you.

It would be nice to have a QR code generator service that allows for some simple analytics which do NOT break privacy (if that's even possible). Of course, it must be based on a zero knowledge structure so that even Proton can't access the data.
In short: It would be cool to have analytics without sacrificing privacy (again, if technically possible).

Maybe Proton can pull this off with all its know-how and I think it would be a sweet addition to the suite!