Nostr is all based on anonymous cryptographic identifiers, so it seems like you have some special definition of anonymity that you are looking for, as it seems nothing if not anonymous. Having a stable identifier allows relays to know who to send versus who not to send, and allows connecting data together. Users are free to sock puppet up to their hearts content, if they wish to further diffuse traffic.
The appeal? The appeal here is that this is an incredibly malleable & comprehensible low level tool for messaging. Competitors like AtProto or ActivityPub involve complex protocols to exchange/syndicate data around, as much as the payload of the messages themselves. They are high level visions for what a network is. By compare, Nostr's low level approach is organic & searching not a refined final product, but a thriving ecosystem of expanding ideas.
Nostr has extreme elegance as a protocol by being focused primarily on messages themselves, which start as very simple & understandable self signing devices. The transport & exchange of messages is almost incidental, and indeed, Nostr over shoebox or carrier pigeon is possible. This allows a lot more flexibility with how the network can form distributed connections, allows great offline capabilities, allows creative relays & creative/selective distribution mechanisms to form.
Nostr is an excellent base layer. The base specs are quite short & direct. It's a protocol one can happily implement in a weekend.
Nostr has incredibly wild applications, because it is a simple extensible base. There's a wide variety of interesting capabilities that have already need accepted as Nostr Implementation Possibilities, NIPS, that grow & build on one another. Nostr base protocol is just a start, just the seed of an idea, one that's meant to be iterated on & expanded, and it's so easy & direct to do so. This is the biggest advantage by far; I cannot stress this enough. Not trying to do absolutely everything & making a modular simple protocol to start building & iterating from is all the wins, is the Bazaar to the ambitious Cathedrals. https://github.com/nostr-protocol/nips
Nostr is by far the most malleable, most open set of possibilities, the most grow able, of the social networks we have. Everything else seems to have been designed to arrive somewhat fully formed, ready to go, but Nostr's strength is that it doesn't purport to know every use case & to have a total picture of what it is. It's a much simpler idea, with much more focus on finding out the uses.
What's charged is my mindset. I'm no longer coming with such a view of scarcity. Of insisting we work together.
You know who gets everyone in a big meeting room & then decides what to do & builds that architecture out? Corporations. In contrast, I think the organic growth model is a huge win here. We can cover more ground, better assay where the rich & nutritious veins are, better explore the many ecosystems of possibilities with an organic model.
It's all still so early, we're so young. ActivityPub, Nostr, BlueSky/@.... they barely have antecedents and none are proven. We are in free-form mode, none of us know what to do yet. You mention RSS, but that's a read-only medium. That attempts to explore the bounds of that didn't get that far: Google Buzz, the Salmon Protocol. OpenSocial. They weren't necessarily bad techs but we never really figured it out, democratized it, pulled it off.
We have multiple different explorers now, and I like it. The ability to keep making useful growth, is, I think, what counts here. ActivityPub has shown some decent flexibility in going across-mediums, but we don't have a ton of extensions, a ton of new modes for it (I think Akkoma, an Elixer-based fork of Pleroma is the most boundary-pushing, and reaction-emoji is their main defining claim to fame). BlueSky is brand new and we have no idea how far it'll go, but it also has a lot of really neat compelling web-oriented ideas in it's core, of signed DIDs that let it be web without having to rely on http:// and dns:// and give us self-sovereignty. Nostr I think is incredibly fantastically compelling, for it's hackability, and what a huge roster of incredibly smart & sharp "Nostr Implementation Possibilities," (https://github.com/nostr-protocol/nips). What a beautiful phrase that captures so much essence of where we are: finding possibilities.
Right now, we need to emerge a shit ton of complexity. We need really wild off the wall stuff. We need lots of ideas & possibilities. We need growth & exploring bounds. Once we have some actual experience building these things & running them as smaller scale individual/microcollective operators & peers, I think then we can focus a lot more on narrowing down & coming together & deciding where and how to meet.
But asking for a github replacement seems like way too much scope. Github is millions of people-hours of work, does a crazy large amount of stuff.
Just start with some basics: can I get a stream of commits from someone? Can I send patches ("pull requests") to someone? Find some managable goals, and build protocols forwards.
The product minded "deliver me a complete replacement for a whole (& massive) product" is a harm-inducing act that obstructs incremental growth & genuine sucess. Nostr has NIPS, Nostr Improvememt Possibilities (NIPS)- trying to coax some wildcard team into writing either one massive NIPS and a huge product or a sea of closely interlocked NIPS and a huge product is going to cause longstanding damage & an inability to grow this organic system out right.
So at least I made some money from this. :)
I'm following the project/protocol, it seems interesting. Here are some NIPS https://github.com/nostr-protocol/nips
Since it is vapourware and you mention the goal of the community participating, please take a look another twitter-alternative as example of that, particularly on the nips: https://github.com/nostr-protocol/nips
That one is open at the protocol level with several implementations of clients and nodes on just about any relevant programming language.