Do you believe in a winning strategy for online casinos?

I have tried several variations of what I believed to be winning strategies for online casinos, including probability theory. Flipped through a lot of research, but it didn't give me the results I wanted. Maybe you have some thoughts on this?

I wonder what you mean by desired outcome? If you want to win it all at once, no proper strategy will give you that, it's a trivial marketing attention grabber. You could try to follow Treasure Island tips https://treasureisland.games/strategy.html , they have outlined some strategies that can give a high percentage of return to the player if used correctly.