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

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

RTP is a long-run average, not a session promise: 96% RTP means a 4% house edge over time. Volatility describes how uneven wins and losses can be. In a short session, results can differ sharply from the average, and you can lose your stake.