Here's what I would do.

1. Make it QR code scanning instead of tapping so it can be a PWA.

2. Make it a PWA. This will make it accessible to many more people. Nobody wants to install an app. Nobody wants to install a PWA either but they will at least use a "web site" (a surprising number will install it if it's good).

3. Save yourself a lot of money by building it on top of the Nostr protocol. Run a relay yourself if you want guaranteed reliability. Run a Blossom server for media. Use email for auth and store people's keys for them if you want a traditional UX. Don't worry about what's on Nostr already, just build your own thing on the protocol.

Let people come and go as they please and don't lock them in. They will love you for it later.

Cool project. Have fun!