How to revert to prior OS. 26.2 is awful.

Rolling-back to an earlier version of iOS/iPadOS is not possible. Perhaps consider that iOS/iPadOS updates include both functional and essential security updates. Restoring an earlier version of the OS would undermine the security of your device and your personal data. 

All System Updates are digitally signed by Apple - and can only be installed whilst the digital signatures remain valid. After release of a new iOS/iPadOS version, the immediately preceding version continues to be digitally signed by Apple - however, usually within a few days, Apple will revoke the digital certificate with which the earlier version is signed.

If your iPad is not operating as expected, try a forced-restart - as this will often clear an isolated or post-update software issue:

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 the problem persists after performing the restart, 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 would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively 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

Multitasking - Split and Slide Over views

iPadOS multitasking has received a significant makeover from that to which you may be accustomed in iPadOS 18.x and earlier - and may take a little time to learn and adjust your workflows. You would be well advised to review the official iPadOS User Guide and the many available online tutorials (such as YouTube) to become better acquainted with the new multitasking interface and associated gestures and controls.

Start here, beginning with the opening video inset that provides a very helpful introduction to the revised multitasking environment and its operation:

Multitask on iPad with iPadOS 26 - Apple Support

These resources may also help:

Work with multiple windows at once on iPad - Apple Support

OS - iPadOS 26 - Apple

If after review you continue to have difficulties, please don't hesitate to return here for explicit guidance.

Apple has never supported downgrading to a lower iOS. But you can minimize the effects this way:

Reduce Liquid Glass Effect: Fortunately, you can adjust this effect whenever you want. It should be turned on by default as soon as you install iOS 26, but you can tweak how transparent your iPhone looks. Here's how:

• Open the Settings app.
• Scroll down and go to Accessibility.
• Tap on Display & Text Size.
• Turn on Reduce Transparency. 

This user tip should be helpful.

Liquid Glass - Love It Or Hate It - It's … - Apple Community