Slow performance after iOS 26 update on iPhone 14 Pro

There is a LOT of background processing that has to take place after a major upgrade. Performance may suffer and the battery may seem to drain more quickly for a few days.

Give it time to sort itself out. Keep it plugged in and connected to wifi when possible to help accelerate the process.

That is normal shortly after the update. You should also experience increased battery drain and the phone will be warmer than normal. Most will see that for 3-5 days, but there is no exact amount of time that applies to everyone. It will depend on the size of your photo library for object detection algorithms and the files being indexed. The same was true for the update to iOS 18 and also expected on point updates to a lesser extent.

About Apple software updates - Apple Support

Obviously when you updated is important to know, but without any idea of knowing when that was, that is the first thing you should expect.