Yes, this makes perfect sense to me. That's also why I only want to change two specific parameters (localpart_template and display_name_template) and not the whole OIDC setup, which should be unmutable so to say. And in my case, I also wanted to ensure that email_template is kept in sync with the Cloudron account email, only giving freedom to set a desired handle and display name (although that one can be modified afterwards by the user).
P.S.: I did not test yet if other settings are persistent or not, as I intend to set a retention policy for synapse as well.