I have created https://jira.kopano.io/browse/KK-2 to follow this up. For us this is no priority though, but outside contributions are welcome! (for example through Github at GitHub - Kopano-dev/konnect: Kopano Konnect implements an OpenID provider (OP) with integrated web login and consent forms.)
Theoretically speaking. shouldn’t it be enough to add some more local proxies to your webserver, so that it internally redirects oidc/endpoint/provider_name/ to konnect/v1/ ?
This was your #3 in the initial post, correct? At the moment this is not possible. You can see the available values for example in https://github.com/Kopano-dev/konnect/blob/master/cmd/konnectd/bootstrap_ldap.go#L53 and konnect/README.md at master · Kopano-dev/konnect · GitHub