It is a standard proposal, which is why it's in the standards track. The point was that it is not the only (the) standard, and not the universally accepted one.
- As a practical matter, anything that is a Proposed Standard RFC is a standard. In principle, there is a two-level system with PS and Internet Standard (down from three levels) but most WGs don't bother to advance specifications past PS. For example, TLS and QUIC are both PS.
- RFC 9580 obsoletes RFC 4880, so from the perspective of the IETF, it supersedes it. Of course, this doesn't make people do anything.
- As a practical matter, anything that is a Proposed Standard RFC is a standard. In principle, there is a two-level system with PS and Internet Standard (down from three levels) but most WGs don't bother to advance specifications past PS. For example, TLS and QUIC are both PS.
- RFC 9580 obsoletes RFC 4880, so from the perspective of the IETF, it supersedes it. Of course, this doesn't make people do anything.