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

https://varimail.com/articles/does-session-timing-matter-in-online-casinos/

RTP is a long-run return; the house edge is the casino’s statistical share: 96% RTP = 4% house edge. Volatility affects how wins and losses arrive. In a short session, results can be far from the average—RTP doesn’t guarantee a payout.