Hardware backed attestation isn’t about security or privacy, if you can’t pass SafetyNet on your Android device you can’t install certain apps, but even with stock software and passing SafetyNet you can still install malware direct from the App Store, it’s about vendor lock in, always has been.
Seconded, I always give the same advice, do something you’re actually interested in doing.
Partly because it can help keep your interest through the pain of learning, and partly because every software dev wonders “does anybody even want this?” And usually you’ll find your market by creating something for yourself.
If I ever get into smart home crap, I’ll definitely be aiming for a local network solution >_>