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

https://gregorysbestchat.bearsfanteamshop.com/variance-vs-volatility-in-slots-are-they-the-same-thing

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.