iPad Air 4 (2020) – iPadOS 26 causing lag and performance issues

Having updated to iPadOS 26, your iPad will initially be performing a lot of background housekeeping tasks. This takes some time to complete as your iPad is re-indexed and new assets are downloaded and installed. Typically, this process should complete in a day or two - during which your iPad may exhibit degradation performance and higher than normal battery usage.

Performing forced-restart will usually clear any stuck/stalled processes:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

If normal battery utilisation does not return within a few days, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:

How to back up your iPhone, iPad, and iPod touch - Apple Support

When you are happy to proceed, you can perform the reset from iPad settings:

Settings > General > Transfer or Reset iPad > Reset > Reset All Settings

If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Otherwise, you might be well advised to seek assistance directly from Apple Support - and request a remote diagnostic test of your iPad. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assist with troubleshooting:

Genius Bar Reservation and Apple Support Options - Apple

have you tried the forced restart?

1. Press and quickly release the volume button closest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button until the device begins to restart.

Best way to improve performance? Accept any and all app updates, cool it with the restarts, wait. Within a couple of days or so, most of those issues will resolve.

You mention how long it has been since the update and how many time you have restarted it. Did you ever let your iPad complete the installation and process its indexing to completion without interruption? That can take a while, and the restarts won't help the process. Reinstalls restart it.

Of course it's still there. I have the same issue on my iPadPro 12,9 M1. The liquid glass etc is too unbalanced in this first version. One option you have is to reduce motion in your settings under accessibility. Then your OS will be less laggy but also less beautiful. Or you wait for the next software update.. maybe they'll patch this issue.