satellite.earth is the communities driven app. Not sure how the development is coming along, though, but it's a good browser based client. You can always use Spring with it on mobile.
Discussion
But Spring + Satellite does not seem to support Amber.
From memory, Spring only stores your nsec in your phone, Spring is essentially a key-signer. Can't remember off top of my head who the dev is, perhaps nostr:nprofile1qqsph3c2q9yt8uckmgelu0yf7glruudvfluesqn7cuftjpwdynm2gygprfmhxue69uhhyetvv9ujuem9w3skccne9e3k7mf0wccsz8mhwden5te0dehhxarj94ex2mrp0yhxgetjv44hymmnwvhx6ef0qyghwumn8ghj7mn0wd68ytnhd9hx2tcwsryw4 knows more?
He's an animal. 🥂