I'm coming from a 6 Plus, so am used to a big phone. I'm also a big guy (6'2"), with big hands.
I don't think the size is that bad - although as the entire thing is one big screen, reachability does become a bit more of an issue. Even reaching the top row of numbers when entering the passcode, with one hand, becomes an issue.
It's the weight that no reviews seem to be really mentioning. Maybe it's because tech reviewers review and upgrade to all the latest tech, so compared to a 11 Pro Max, it's not 'new news'. But due to Covid all apple stores are closed and I couldn't 'try' the phones out before buying.
It really took me by surprise and was almost a deal breaker. I just can't be bothered to go through the returns process!
But coming from a 6 Plus, I honestly cannot believe the difference in weight and thickness, and that more people are not making a bit of a fuss over it... it also feels like it should be a little more 'bottom heavy', so that it's more stable in the hand.
Using the phone one handed while walking, say, to reply to a text, is out of the question for me. Especially as it's so expensive. I am slightly annoyed that I didn't trust my gut and go with the 12 standard 128GB, but I think that I'll see how I get on over the next year or two. I think I'm getting used to it.
I still have my iPhone 6 Plus for occasions when I don't want to take a £1200 out with me! It's not worth anything second hand really, and it's nice to sometimes have a phone that you're not worried about dropping/getting stolen. the 6 Plus feels so good in the hand!
Cheers!