RTP is a long-run average; the house edge is the casino’s mathematical share:...

https://www.bookmarkzoo.win/rtp-is-a-long-run-average-not-a-promise-for-one-session-at-96-rtp-the-house

RTP is a long-run average; the house edge is the casino’s mathematical share: 96% RTP = 4% house edge. Volatility shapes how wins and losses arrive. In a short session, results can differ sharply from the average—RTP is no promise of a return.