Slots can be played profitably. Not just any slot, not just anytime, but some slots become +EV when the jackpots get high enough. Some other games have been profitable to play in the past, after careful analysis by players. "Advantage players" seek these games out and monitor them for profitable situations.

In other cases, there are strategies to just lose less money.

Anyway, all that to say, there's definitely slot advice videos and all that out there.