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

https://astro-wiki.win/index.php/How_Do_UK_Casinos_Make_RTP_Info_More_Transparent%3F

RTP is a long-run average, not a session promise: 96% RTP means a 4% house edge over time. Volatility shapes how wins and losses arrive—steadily or in bigger swings. In a short session, results can vary sharply either way.