You just have to stick to legal, regulated online casino sites such as BetMGM, Caesars Palace Online Casino, FanDuel, Betway, bet365 and BetRivers. They offer great casino game ranges and they will pay out quickly and without any issues if you win.
It's widely accepted among players that the optimal times to play slots are early morning or evening, with peak hours typically occurring between 8 pm and 2 am. Take some time to watch the particular machine to gauge when it is most likely to pay out.
The truth is, yes casinos can control a slot machine or rig it only to give players small wins. Some casinos work with developers to create exclusive games. This gives them even more access to a game's code and RNG.