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

https://johnnysinsightfulword.evergrovio.com/posts/why-do-casinos-always-have-negative-ev-for-players

RTP is a long-run average; the house edge is the casino’s expected share: 96% RTP = 4% house edge. Volatility describes how uneven wins can be. In a short session, results can swing sharply, so you may lose more—or win more—than the averages suggest.