It's tricky because are we talking about regular iPhones or Max ones.
It's really similar to the do I get an older iPad Pro or do I get the current Air debate some have. If you value pro motion, better display, better sound etc the iPhone Pro while older makes the most sense. If you want the top chip possible and love the Dynamic Island, dont care about pro motion, HDR, or camera features then the 15 iPhone is your choice.