It seems that at least the push notification registration part uses a "leaked/extracted" FairPlay private key [1]. As far as I understand, FairPlay certificates/keys should be unique to each iDevice. Couldn't Apple trivially ban all subscriptions originating from this fake device? The comment says you know how to generate more; does Beeper Mini generate one for each install? Why would Apple believe those certificates are authentic?
P.S.: the source repo mentioned in the comment (https://github.com/MiUnlockCode/albertsimlockapple) is 404.
[1] https://github.com/JJTech0130/pypush/blob/main/albert.py#L16