RTP is a long-run average; the house edge is the casino’s expected share: 96%...

https://www.stall-bookmarks.win/rtp-is-a-long-run-average-house-edge-is-the-casino-s-mathematical-share-96

RTP is a long-run average; the house edge is the casino’s expected share: 96% RTP = 4% house edge. Volatility affects how wins and losses are spaced. In a short session, results can differ sharply from the average—RTP doesn’t guarantee a return.