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

https://blogfreely.net/teresa-long85/whats-a-risk-preference-choice-when-picking-casino-games

RTP is a game’s long-run return; house edge is the casino’s mathematical share: 96% RTP = 4% house edge. Volatility describes how uneven results can be. In a short session, variance can swamp the average, so outcomes may differ sharply.