That's fine. It's early days. Things will converge.
Probably not. One did method needs a full Bitcoin node. The other needs a full Ethereum node. The other needs a Solana node. Massive dependencies if you truly want to make DIDs decentralized.
Aaah yes that sounds like a bit of a burden. Those are p2p networks that put a lot of load on the peer and scale extremely poorly overall. Kademlia DHTs like IPFS or Bittorrent scale medium well. It's a question of scaling distributed systems -- my eternal pet peeve, I'm optimistic! -- but not a question of formats or key algos or diverging code bases which is what this conversation was about.