This is my experience as well. I've had the 6+, 6s+, 8+, Xs Max, and the 11 Pro Max. The 12 Pro Max just feels too heavy - I can't stand any case that adds to this phone. Nekkid - the phone feels OK. But I haven't had a nekkid phone since the iPhone 5. While I like the square sides it makes the phone feel bigger - harder to hold.
I wish I had done the mini route. So many people I follow here that did the same and they're happy.
A flip side to the weight issue with the 12 PM - I have essential tremors and the heavier phone helps me keep it steady, especially when using the camera (they even make weighted eating utensils to help with this problem). I even haven Otterbox Defender case on it, making it heavier yet. Certainly an outlier circumstance, but I like the heavier phone.