i will provide a PR as soon as I have a little more time!
Anyway it’s already prettiy easy to do
Copy JwtAuthProviderReader from SS Repo and apply the changes from https://gist.github.com/tobiaszuercher/bd38241975dcbe0adda2ccc2ba547d04 (or just use the gist). Usage is described in IdentityServer Integration possible with JwtAuthProviderReader but needs small adjustment