I agree with OP. The security model is similar to kerberos tickets or ntlm hashes. Revokable Private key authorizarion is the best way to go imho. I don't mean

I agree with OP. The security model is similar to kerberos tickets or ntlm hashes. Revokable Private key authorizarion is the best way to go imho. I don't mean at the transport layer but at the HTTP/app layer. This should replace not just bearer tokens but authentication cookies as well. Each connection is authenticated by the final server. Hopefully you can store the private key on fido or tpm as well to make theft harder, forcing attackers to maintain persitent compromise of your host.