I haven't used revanced in a while, but Fennic + ubo + sponsor block should get you to basically the same place unless they've added new features since I used it last.

No separate app required.

I suspect this is designed to block revanced entirely. It won't be able to install the apk it compiles or downloads, so apps won't be able to update even if you have it installed via adb to begin with.

Shizuku + Obtainium might still be an option.

That's what it sounds like.

They're doing the same thing Apple has been doing for years, I used to run a self-signing application which ran every week or so by itself.

Workarounds are going to exist plenty, it's just a slap in the face. Especially because the Play Store is filled with malware. Apple's strict rules are horrible for developers, but at least it's not as riddled with malware.

All APKs will require a signed developer certificate.

I doubt they will be signing keys for developers who circumvent Google's services, or that violate their ToS.

They're copying this scheme from Apple in Europe, when it was forced to allow other app stores.

In that case, Apple revoked certificates for apps it didn't like, such as P2P/torrents. Mind you, these were NOT apps that were not hosted on Apple's App Store.