In fact it was Gemini, but I don't remember which version and there are big differences. I'm signed up for all the betas and I switch among them frequently.

That's interesting! Gemini has definitely been less sycophantic than GPT but I haven't had it push back unless we were already arguing about something. Claude is the only one I can go to with "I have this great idea for a cool thing that I can make that I think will go hard on the market" (or whatever I've never had this conversation with it lol but similar) and it'll knock me off my high horse quickly.