This got me connected with both Gemini and OpenAI - however on one instance of RCP I loaded my API Key into, it found only 5 models in OpenAI: gpt-4o, gpt-4o-mini, o1, o3-mini, and gpt-4.1. On another machine, with the same key, it found 118 models in OpenAI (I will not list them all). In any case, this solves the main problem with the thread, imo this should be the accepted answer.

This is what solved it for me. I'd suggest this be the accepted answer.

This still works in Xcode 15.4. I added SwiftUI instead of UIKit since I was using that.