RTP is a long-run average, not a session promise: 96% RTP means a 4% house edge...

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

RTP is a long-run average, not a session promise: 96% RTP means a 4% house edge over time. Volatility describes how uneven results can be. In a short session, outcomes may differ sharply from the average, so set limits and expect uncertainty.