Just eyeballing Geekbench scores for iPhones, CPU/GPU/NPU are all about 3x faster, and RAM capacity has doubled.
Do you need all that extra power? I dunno, but it's a pretty big difference.
The latest iPhones are not actually 3x faster, or even 2x faster, for many common tasks such as opening a pdf compared to a 5 year old iPhone on iOS 12. Even for unusually intense workloads, like exporting dozens of pdfs at the same time, it doesn't get anywhere close to 3x.