I have an iPhone 11 that is starting to fail so I guess its time to upgrade but honestly there's nothing feature-wise I can think that I need in newer models and it's been that way for years.
One thing I wish they'd do is have Touch ID as an option on all iPhones, iPads and the Apple Watch. I absolutely hate Face ID. In fact it's ableist, often failing for people who through lack of normal vision have to hold their phones closer to see them.
Just put a touch sensor on the back like the Samsung Galaxy phones used to (and still do?).
But that won't happen. Still, I ditched a perfectly good iPad Pro (with Face ID) to buy an iPad Air (with Touch ID) but that one and only reason.