Hi There,
I’m not aware of anything existing that will do all of this in one app.
We build custom Shopify apps though, if you wanted to go down that path (https://italicsbold.com.au/)..)
From what I gather, you’d probably want a simple mobile app for the customer as well, so they can easily display a QR code which could be scanned. You’d probably need a phone or device on reception that could scan the QR code and display their subscription status etc.
If you’re interested in chatting about a custom app, let me know at nick@italicsbold.com.au and we can organise a time to go over the details.