for android you can take a look at nostr:nprofile1qqszpxr0hql8whvk6xyv5hya7yxwd4snur4hu4mg5rctz2ehekkzrvc64twc2 . The point Miljan makes here does stand, it takes a lot to get a reliable polished product.
Amethyst took a big hit in terms of reliability after their big recent overhaul but i expect things to improve over time (as they already have).
I'd like a native app. Amethyst used to work well but it has always drained battery. Nozzle didn't. Ironically, fedilab seems to work about the best if your account lis tied to a ditto server.
YakiHonne has an android app.....
Ah, not in Fdroid. But it requires an account. Not amber
???
You can download the apk here if need be:
https://github.com/YakiHonne/yakihonne-mobile-app/releases/tag/YakiHonne-1.8.6
Yes, you can use amber, where did you get the notion you could not?
It asks for a account. Probably for a Wallet. 
