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

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

RTP is a long-run average, not a promise for one session: 96% RTP means a 4% house edge over time. Volatility describes how uneven results can be. In short sessions, results may differ sharply from the average—you may lose quickly or win unexpectedly.