Everyone dunks on Apple for throttling older batteries but the fact is this was super pro-consumer move. It prevents the phone from randomly powering off because the SOC tries to pull a burst of energy that the battery is too tired to output, and resets following a battery replacement, plus nobody notices the throttling except under synthetic benchmarks where you actually have performance numbers to see the handful of percentage points of performance difference. AND after this kerfuffle they added a toggle switch where if you so prefer random instability on an aging battery over 2% slower turbo performance you can choose to have that.