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A new release of the OP plugin will be forthcoming this fall or winter that hopefully will address the remaining limitations around pure OAuth usage, and probably will add support for https://www.rfc-editor.org/rfc/rfc9126. It seems to be an intention of this new spec to facilitate decoupling RP URLs from OP configuration, which fits nicely with the direction of relaxing registration requirements for clients to add deployment flexibility. If both clients and resource servers can be used without registration (apart from having a mechanism to authenticate them via service accounts of some sort), many campus deployment scenarios become potentially very lightweight for both the OP and the endpoints.
In addition, collaborations with member organizations in Europe are underway extending the OP feature set with some other in-demand features, and we will obviously be able to incorporate that work into future releases.