Earlier quoted context omitted.
No that’s because your battery is old. Swap the battery and that “slow old phone” suddenly has the exact same speed as the current flagship
Yes and no. Yes, iPhones get throttled when the battery is on the verge of going ex, but no for this particular device. I run an iPhone X with a new battery from November 2021 (serviced by Apple), with maximum capacity at 90%, and it really is slower compared to the old days. But! I'm not complaining. It's an almost 6 year old device. That means, for every year of usage, I payed roughly 200€, or 16€ per month. That's…
Though I agree that battery health hasn't been super important to performance. But resetting the phone can do wonders