[SOLVED] alternative to `users.*.create` function event with OAuth login?

I'm using the Google OAuth login in my app, and want to run a function on each user creation. But as of now, it's not possible due to a bug (ref). My main plan is to create a document under the "Users" collection on each user creation. So can anyone think of any alternative/workaround to it?

TL;DR

The user wants to run a function on each user creation using Google OAuth login but encounters a bug preventing them from doing so. A potential workaround is to trigger a function on session creation, check if it's an OAuth session, and fetch the document to see if it already exists. If not, create it.

Trigger on session creation and check if it's an oauth session and then try to fetch the document to see if it already exists. If not, create it