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

https://wiki-coast.win/index.php/What%E2%80%99s_a_Good_One-Sentence_Definition_of_House_Edge%3F

RTP is a long-run average, not a session promise: 96% RTP means a 4% house edge over time. Volatility affects how wins and losses arrive; higher volatility can bring longer dry spells