RTP is a game’s long-run average return: 96% RTP = 4% house edge, not a promise...

https://www.quantifiedstrategies.com/rtp-variance-and-expected-value-applying-a-quantitative-framework-to-online-casino-gaming/

RTP is a game’s long-run average return: 96% RTP = 4% house edge, not a promise for one session. Volatility describes how often and how sharply results swing. In the short run, outcomes can differ sharply from the average, including losses.