From my understanding, it will only allow apps that were registered, so since ReVanced uses identical package names to the patched apps, it probably won't work unless they start using ReVanced-specific package names that are tied to their identity. But that would allow Google to block these package names (or ban ReVanced completely) if say, Spotify or YouTube complain about them.

What if I come up with a random package name, like "online.discuss.jim3692", register that name and a keypair, and then build ReVanced using that name and keys?