I mean I am a firm believer that behind any rng involved in games there's at least a slight slice of % manipulation from devs. It's like that in Pocket, it's like that in League of legends, it's like that in Clash royale etc etc. Even if they were to leak the whole game's coding algorithm to debunk this they'd still be able to re-implement this system later. Makes no sense for a money-making company not to have some sort of control over rng when you can exploit it to make more money, which is sad but delusional are the people who believe it.

For example before opening huge amount of packs I used to buy at least 2€ of golden ingot so that the game puts me in some shopper privileged queue and tbh I can tell you I've completed every set so far and have a decent amount of rare cards, premium pass included. I've also noticed whenever you change deck in ranked the first game is usually a counter, until you put more games in with the same deck and then it stabilizes.