Thanks @DudaNogueira for the details!
The part that I was missing was that the X-OpenAI-Api-Key header passed into Weaviate would ultimately be passed through the text2vec_openai vectorizer as an Authorization Bearer token to whatever base_url we set. It was a little unintuitive but should work for our use case. I’ll continue down this path and hope that this will keep our services up when OpenAI APIs (inevitably) goes down again.
And just to confirm, as of now there is no way to update an existing collection with a vectorizer base_url change without having to migrate to a brand new collection + updated vectorizer configuration correct?