I think you're looking at this all wrong. If Telegram did this officially with Google, would they have had to craft this klunky workaround for breaking up RPC strings and randomizing the user agent? I don't think so.

Also the Google Pay analogy seems off. Telegram backdooring free access to Google Translate is not at all the same as Google partnering with 4 banks for transaction processing. One is totally unofficial, the other is an actual partnership.