If there was a fully functioning website that tells you which slots out there are profitable and which are not, it would have been closed a long time ago. The gambling industry is one of the biggest and best protected in the world and you know what they say "the house ALWAYS wins"
Is there any slot that developers created in order to profit players? I highly doubt that so what you say is nonsense. None website can tell you profitable slot because such thing doesn't exists and no one can tell you exact strategy to beat slots. What about if I would say that slots learns from you too? Learns your strategy and plays against you with better brain than you have?