RTP is a long-run average, not a promise for one session. At 96% RTP, the house...

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 promise for one session. At 96% RTP, the house edge is 4%: about £4 per £100 wagered, on average. Volatility shapes the swings; over a short session, results can be far above or below that average.