Good to hear from you, and glad your friend is giving it a try.
An Android app is something I want to build — I know plenty of people aren’t on iPhone — but I can’t give you a timeline yet. Right now I’m focusing on adding features to web, iOS, and the MCP server that I think will make a real difference, and I’ll take the learnings from iOS to fast-track Android.
The good news on Garmin: he can enable the Garmin integration and give Tempo permission to store health data like resting HR, HRV, and so on. He’d just need to use the web version on mobile for now.