According to the story at wccftech, the new iphones don't take full advantage of wifi7, so it isn't worth it to buy a new router.
iPhone 16 Promises Blazing Fast WiFi 7 Speeds But A Hidden 160 MHz Limitation Is Secretly Keeping Performance Stuck At WiFi 6E Levels
The WiFi 7 speeds on the new iPhone 16 and iPhone 16 Pro models is on par with WiFi 6E from last year, as Apple has secretly capped the functionality.
wccftech.com