RTP is a long-run average; the house edge is the casino’s expected share: 96%...

https://city-wiki.win/index.php/Why_Do_Casinos_Always_Have_Negative_EV_for_Players%3F

RTP is a long-run average; the house edge is the casino’s expected share: 96% RTP = 4% house edge. Volatility affects how wins and losses are spaced. In a short session, results can differ sharply from the average—RTP doesn’t guarantee a return.