RTP estimates how much a game returns over a very large number of plays; it...

https://www.quantifiedstrategies.com/rtp-variance-and-expected-value-applying-a-quantitative-framework-to-online-casino-gaming/

RTP estimates how much a game returns over a very large number of plays; it doesn’t predict your session. A game with 96% RTP has a 4% house edge on average over time