I tried this last summer just using free Chatgpt and I was shocked how much it could do. We used it in audio mode where we just spoke our actions and the iPad DM spoke back. We told it to do some really silly stuff and I can't believe how amazing it was. An example was we asked if there were tapestry on the walls and it described them in great detail. We then said one of our characters tore down the tapestry and made a jacket out of it for a friend. It handled that incredibly well and it even lead to a problem later on. Were you typing and reading or was it all speaking? I don't know much about Gemini but it seems like you get charged per token used. Do you have a quick tip on how to get what you need to play for the cheapest amount?