I did exactly this. Originally upgraded from the 15 Pro because I hated the battery life and its poor thermal envelope. Admittedly I am a heavy user so I was charging the 15P halfway through the day. Great phone on paper but it was my least favorite iPhone since the 6 Plus.
Anyway, I originally pre-ordered the 16 Pro Max and used it for a day or so but for some reason, got scared by its larger size and weight over the 15P. Then I impulsively exchanged for a 16 Pro and while I enjoyed it mostly, thought that if I am going to upgrade after only a year, it might as well be "worth it". Yes, the 16P's battery life was an improvement over the 15P, but I realized I made a knew-jerk decision and actually missed the massive screen and battery life of the 16 Pro Max.
Yes, the PM is bigger and heavier (especially in an Apple Silicone Case), but it's not that bad. Without a heavy case, it's not bad at all. Battery anxiety is gone and I've stopped carrying battery packs or chargers with me, so effectively it's lighter for me, day to day. I may get one of those "barely there" thin Totallee or Peel Case, so weight will be reduced further.
Plus, I really appreciate the larger screen as I scroll through the Web wherever I am. After using the PM for a few more days, I don't even notice its size, but what I do notice is the incredible battery life and what I think is the best mobile web browsing on a phone- keeps me from buying an iPad. In fact, I now set the charging limit to 85% and still make it through a day of CarPlay and heavy use, from 6:30 AM to 11:30 PM above 40%.
General comment on the 16 Pro series- this is what the 15 Pro series should have been. This is all around a much better phone in terms of UX. Call it an "S" year, sure, but that was the beauty of those phones- they were just that much more polished. I may actually keep the 16 PM two or more years, whereas I couldn't wait to get rid of the 15P after 6 months or so.
TL;DR: Go for 16 PM- you'll appreciate its battery life, screen, and will get used to the size.