A lot of those pain points are involved by virtue of being the original developer. Generating a QR code every single minute for every single user can indeed easily lead to issues, but that's much less of an issue when you're able to change the QR code validity to, say, a week.

If you use online validation you can even dynamically rotate them whenever it suits you - either to adjust server load, or as some kind of "every Nth check-in" scheme. Heck, with online validation it doesn't even matter if the rotation service goes offline for a while!

Or just generate a fixed QR code which never changes. You know, like the 8-digit pin the QR code is the alternative for.