iOS 26.5 device lags and freezes on home screen and in apps

Not sure what left corner + icon you are referring to on the Home Screen, could you provide more information on where you are seeing this icon that causes the screen to lag?

Force Restart your device. This will do some basic housekeeping and especially useful after a Software Update:

• Press and release Volume Up
• Press and release Volume Down
• Press and HOLD Side button until the Apple Logo appears. This could take up to 15 seconds while holding the side button before you see the Apple logo and you have to ignore anything else on the screen during that time including the Slide to Power Off prompt. If you don't see the Apple logo while holding the Side button, try again as it may take a couple of attempts to get the speed and sequence of the key presses correct.

If it has not been 4 days since your iOS update, then it is likely that background processes are still being performed to index the new files and perform object detection algorithms on your photos. Not only will you experience lag during this time, but also increased heat can be felt.

About Apple software updates - Apple Support

Third party apps can lag while scrolling depending on their data prefetching routines and internet connection speed to retrieve that data. Google and WhatsApp are not apps that are good benchmarks to determine a performance issue with iOS 26.5. Are you experiencing the same lag in scrolling with the Messages app or scrolling through your photos?

ThorendorToo wrote:

Same thing for me. When I press the right side button, to turn off my phone hone then press it again, the app will mostly often become responsive again. I’m also getting ghost clicks that cause pages to scroll or jump to the top. Occasionally the ghost clicks happen on the keyboard and random text gets entered.

"Ghost" touches are a sign your Digitizer is failing. If that is what is happening, it will get worse and for some those ghost touches will happen on the Unlock screen and too many invalid entries will lock them out of your device. The only solution for that is a screen replacement as the Digitizer is built into the screen. While this happens frequently when there is a crack in the screen, of course this failure can occur at any time.

Another common cause to what you are experiencing is due to your Battery Health. Go to Settings > Battery > Battery Health and if it is below 80%, the battery needs replacing and you are likely also seeing the Service Required message in your Battery Settings that confirms you are in need of a battery replacement.

Same thing for me. When I press the right side button, to turn off my phone hone then press it again, the app will mostly often become responsive again. I’m also getting ghost clicks that cause pages to scroll or jump to the top. Occasionally the ghost clicks happen on the keyboard and random text gets entered.