iPadOS 16 not working with the Spectrum app and the Apple AV adaptor

Rolling-back to an earlier version of iOS/iPadOS is not possible.

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 Apps no longer work properly following update to a more recent version of the OS, you’ll need to seek assistance from the related App Developer - as only they can resolve issues with their App.

How to contact an app developer - Apple Support

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. 

For information, Apple do invite submission of comments via its Product Feedback portal. For iPad and iPadOS:

Feedback - iPad - Apple

As for difficulties with your AV Adapter, presumed to be the Apple Lightning to Digital AV Adapter, can you describe the problem? Are you experiencing difficulty with all media, specific content, or just with a specific App?

The more information that you can provide about the issue that you currently have, the more likely a contributor will be able to offer targeted guidance or help.

Per my second reply, rolling-back to an earlier version of iOS/iPadOS simply isn’t possible.

Are you aware of others experiencing issues?

Unless you provide more details of your precise problem, as already requested, it really is very difficult to provide appropriate advice to address the issue.

If you are simply looking for a channel through which to express your frustration directly to Apple, you can use the Product Feedback portal:

Feedback - iPad - Apple

Thanks for the additional information. As described, both your iPad and AV Adapter are technically good - and working. If the AV Adapter wasn’t working at all, with any streaming App, you might reasonably conclude that the problem was with iPadOS or the AV Adapter.

As is, the issue genuinely appears to be the Spectrum App and its compatibility with iPadOS 16.3.1.

While Spectrum Technical Support may be finger-pointing elsewhere, they may simply be (a) unaware of the problem - or (b) have not provided their support agents with useful information to provide to customers. While we have no way of knowing, they may be working in the background to trace and correct the issue with their App.

At present, you are in the unfortunate position that Spectrum are either unable, or unwilling, to offer appropriate assistance at this time.