I don’t think it’s open source but we use our groceries. Just links to an email only no password. They just send you a code when you link the email to a new app. It’s also cross platform if that matters at all. Also requires no permissions granted to run and only requests a camera permission to scan barcodes.

Google play link

All the Jellyfin votes had me downloading it and before it even got downloaded you changed my mind lol. Just gonna stick with plex. I like simple and already have the lifetime sub.