I got the 12 on Monday. I immediately felt that it was slightly wider and taller than my X (which I have to adjust in my hand to use it fully). I just thought to myself “yeah, I can’t be bothered with this now. There’s a mini, just get that instead”. I did try it a few times, but I never actually set up my 12. I’ve emailed the case manufacturer to swap my order for a 12 mini one & I’m going to the Apple store tomorrow to return it.
I am nervous about the battery life on the mini though. My X is on 89% battery health after a year with a new battery & I doubt it’ll be that much better than my X was with a new battery.