Recently upgraded to the 15 Pro...but before, I had the XR.
Needless to say, I kept my XR because its durability, longevity, and performance were unmatched, and I saw how fragile the new iPhones were made to be.
Now, I'm about a month or two into owning my 15 Pro and it is..actually quite good. I'm simple, so my goal was to have a sick, modern phone with a spectacular capacity for photography/videography.
*Also didn't want it to shatter.* So far, it's lived up to that.
IMO, most important is the protection you give it (well-acclaimed cases/screen protectors) as well as how you treat it.
Also, what are you waiting for, really? Apple seems to pop out new iPhones left and right these days, when really is the right time? The iPhone 15 Pro is pretty cool, and seeing as manufacturing quality is on an endless decline these days, I wouldn't expect iPhones to be better equipped [than the 15 Pro] in the near future.
Godspeed!