Unfortunately as far as I can tell the documentation doesn’t cover my questions. My OAuth configurations are working as expected, it’s only the additional functionality outlined in scenarios 1 & 2 that cause trouble.
What I’m looking for is something along the lines of an optional parameter, callback_url, that would redirect the user to its target URL, after the OAuth provider has verified their account, and returned them to Discourse.
I guess it’s sort of as if my Discourse instance acted as an OAuth provider in and of itself, for my Flask/Python app?
E.g. https://discourse.example.com/auth/google?callback_url=https://example.com/home takes the user to Google, returns them to Discourse, which in turn redirects them to callback_url.