Atproto has more in common with Keet than nostr, but neither atproto nor nostr solve the social media bigtech dilemma as the basis of that is using servers and only keet has solved not using servers
It won't disappoint. It's basically just about ready to replace Signal , WhatsApp etc and more, they have livestreaming in public testing now too and heaps of features coming
Keet 3 years ago didn't support mobile and had a group chat limit of about 50 people. It now supports mobile and has no group limits with one group already with 13000 people, it has a heap of new features including things like livestreaming