I just tanked my XS Max in the river so I was forced to upgrade to a 15 Pro Max. My observations:
- The display quality improvement is noticeable, especially in bright situations and I actually enjoy the always on feature.
- Magsafe is way more useful than I expected, although I had a MagSafe-like case on my XS Max (magnet wasn't nearly as string though in many situations).
- USB-C... Meh, I've had several USB-C ports fail on MacBooks and iPads. I always found Lightning to be reliable. But thanks to Qi I almost never use the port anymore (wish the iPad Pro had a Qi option).
- I find the action button mostly useless, same with my Apple Watch Ultra.
- Cameras alone are worth the upgrade.
Overall though, I probably would have kept my XS Max until no more OS supported updates.