Unfortunately, this is not 100% correct information. RTP can be adjusted and that is why different casinos have 1-2% difference for same slots by same provider, casino can decide which option is best for its own advantage. Negative thoughts is caused by house edge which is unbeatable in the long term, as explained before players can't beat the casino but player can.
Not entirely sure but when a casino is using a game provider then RTP and such things are not in casinos control. The provider adjust it depending on the game. The casino is only responsible to bring clients in their platform and let the clients to play. Bet history and everything else except customer management are done by the provider.
These days unless you are a big casino, you can not afford your own system. You are just using others API. I guess bet365 are big enough to have their own game engine and sports engine. I could be wrong.
Basically it's like affiliate network. Imagine I am a farmer and I sell oranges, and there is someone who eats oranges, how would I make sure that they eat my oranges? I find a seller, and that seller goes out and find people who eat oranges and sell my oranges to them. In this scenario Stake basically finds games from others, and find a ton of customers, then brings those games to their customers and they do not have to worry about anything else but finding customers that's it, wins and losses all matter to provider, not to stake.
This is how they just make pure profit, and with tens of thousands of customers, they make some sweet sweet profit for sure, all those drake and nba etc etc deals were made with that kind of selling talent.
From my u understanding of how casino games work, it is clear to say that not all games are owned by a casino and sometimes casinos collect games from other providers and with their smart contract every revenue generated by the activities of the game on the thirds party casino a percentage devision will be split between both the game provider and the host casino.
This is a partnership contract and it is well known, so same with stake any game that is not in the house belongs to third-party providers and the rules may have effects on the outcome of the functionality of the game on the casino including the amount of payout and even KYC demands.