RTP estimates returns over many plays: 96% RTP = 4% house edge, not a promise...

https://josuesexpertblog.novacrestiq.com/posts/why-do-two-slots-with-the-same-rtp-feel-totally-different

RTP estimates returns over many plays: 96% RTP = 4% house edge, not a promise for one session. Volatility shapes how wins and losses arrive—steadily or in larger swings. Short runs can differ sharply from the average, and you can lose your stake.