RTP estimates a game's long-run return: 96% RTP means a 4% house edge....

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

RTP estimates a game's long-run return: 96% RTP means a 4% house edge. Volatility describes how uneven results may be. In a short session, you can win or lose far more than the average suggests; RTP is no guarantee of an outcome.