Fedify has just laid out a comprehensive implementation plan for this fep:
FEP-ef61: Portable Objects · Issue #288 · fedify-dev/fedify · GitHub
The core idea is replacing HTTP(S) URIs with server-independent identifiers:
ap://URIs that use a Decentralized Identifier (DID) as the authority component, rather than a domain name. An object identified asap://did:key:z6Mk…/actorcan live on multiple servers simultaneously and survives any single server disappearing.