Is that the right product though? I use office 2019 and that says to activate but mine's activated - I need something to stop the remotely bricking.
Maybe deleting the updater will work? (as in https://osxdaily.com/2019/07/20/how-delete-microsoft-autoupd...)
It won't help, sadly.
Your Office has a license file - you could have bought it or pirated it, doesn't matter. This license file is signed by Microsoft, and Office determines if the signature is correct based on the certificate that is embedded in the Office instance. If the signature is correct, Office trusts the contents of the license file to determine what you can and cannot do.
Starting July 14th, the certificate itself that provides a public key for license signature verification will be no longer valid. So when Office will try to validate the license signature, it will no longer find any matching trusted certificate that is still valid, and conclude that it's not licensed anymore.
Indeed Microsoft can issue a newer certificate with an expiration date set in 2099s, but they wouldn't. So far pirates relied basically on an official method of activation (not a crack). Now we need an actual crack that would either make Office think its certificate didn't expire yet, or skip the signature verification altogether.