Have you already tried editing the manifest? You can do it safely as long as you take simple precautions.

Instructions:

Open the run dialogue with Windows R and type the following: %appdata%

Find and open the NVDA folder.

Go to the add-ons subfolder, and find within that another folder with the name of this add-on.

Within that, find a file called manifest.ini.

Open the context menu on that file and use the (open with) option to open the file in a text editor like Notepad.

Find the line that says: lastTestedNVDAVersion =

Copy the number that is currently there and save it somewhere safe.

Now change the original number to 2022.1 and save the file.

restart NVDA, and if you can still use the add-on just fine then you're good for a while longer.

If it fails to work then edit the manifest file again and change it back to the previous number and restart NVDA.

This process works the same for all add-ons, though keep in mind that occasionally an add-on that fails to work with this process will cause NVDA to crash, which means you need to know how to use Narrator or another screen reader in at least a basic way just encase you have to fix the manifest without NVDA. Alternatively, backup portable copies of NVDA work great too and are super easy to make. Just memorize the path to one so that you can pull up run with Windows R and type it in if you need it even without speech.

Why not contact the author via the plugins page/thread and ask them to update?

When I look for audio theme nvda I find this: https://github.com/blindpandas/Audio-Themes-NVDA-Add-on

What is it you need changed? Do you know?

In general you should never have to downgrade for a plugin; if you feel tempted to do so, something is wrong.

For security and other computer reasons you should not do it. As a person working in the tech field, and no one competent in the tech field should recommend you do so.

Please keep all software up to date and maintained.

Given how laggy that thing was every time I tried it, I'd say not worth it. It'll get updated eventually, so you can try it then, and probably discover you prefer your screen reader without it anyway.

Depends on the add-on. I kept back from updating until NVDA Remote was ready. IBMTTS would probably keep me pinned too. Other than that, no.

I’d do it if you enjoy it.

I don't know, but every time I go to update, it says my eliqucence voice won't work. It is a problem for me to find where to get latest compatible version.

The old version, well, it's old. So if you don't mind losing what's latest and gratest, there's no harm in downgrading. I also keep several portable copies of NVDA for same reason. If new breaks, I go back and install from portable.
There are some security considerations, but unless you are garding state secrets in your system, or working in corporate environment, don't think we will need that kind of marginal security improvements.