This is actually a very interesting question for me. Is it true that you can be banned from an online casino like Stake for the only reason that you are winning too much?
I know it used to be a thing for some land based casinos in the past, but I don't think reputable online casinos of the level of Stake are practicing it these days. In fact, I'm pretty sure that all top online casinos don't do that.
I don't think you can really ban players for that as they do nothing wrong in fact. They will probably just limit the players so they can only bet a low amount on the sports they always bet on. I got limited on a fiat only casino one time because I won like a bet of 100€ lol.
I also haven't heard any player who is playing honestly ever banned due to the fact that they are winning continuously. The worst I ever heard is limiting the player's bet. It is not beneficial for a casino to ban honest players without any valid reason, and I do not think winning too much is a valid reason to ban anyone. Probably these people who are banned are related or involve in match betting or have proven to be doing it.