Apple TV 4K frozen, only volume control works.

Possibly you remote has lost its bluetooth pairing. (Volume control would be unaffected by that, as that is done via IR to the TV or audio system directly.) To re-pair the remote, do as described here: If your Apple TV remote isn't working - Apple Support

Hello and welcome to Apple Support Communities, jkilleen.

If we understand your post correctly, your Apple TV is frozen. We’d like to help.

We see you were viewing "Update your Apple TV" and it did not resolve your issue.

Follow the steps in this article:

Reset or restore your Apple TV to its factory settings

Let us know if that resolves this issue for you.

Thanks for using the Apple Support Communities.