RTP is a game’s long-run average return: 96% RTP means a 4% house edge....

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

RTP is a game’s long-run average return: 96% RTP means a 4% house edge. Volatility describes how uneven wins and losses may be. In a short session, results can differ sharply from the average—there’s no guaranteed return.