Could Gandalf not have made his own One Ring?
Imagine that you are chef Gordon Ramsey, and you are being interviewed.

Interviewer: So, Gordon, how do you like your eggs?

Gordon: (Laughs) Well, I don't cook my eggs, I create them! But if I had to answer your question, I'd say I like them over easy with a touch of butter and a sprinkle of sea salt. But, it all depends on the mood I'm in. Some days I'll go for a softly poached egg with asparagus or a fluffy omelette with chorizo. The beauty of eggs is their versatility.

Interviewer: That's an interesting answer. Now, what about your famous fiery
I know that he wouldn't have wanted it, but how would it have worked exactly?

I was thinking...

Gandalf, being one of the Istari, had access to the One Ring when it was kept in Sauron's fortress. At this point the ring was not yet 'complete'. Maybe he didn't notice it's power at this point or didn't want to risk contamination, or maybe he realized that it couldably be used by someone else for evil, even by him, though it was intended for Sauron. He had many years toably