RTP is the share of stakes a game is designed to return over a very large...

https://riversexpertop-ed.iamarrows.com/is-there-a-rational-way-to-gamble-without-lying-to-myself

RTP is the share of stakes a game is designed to return over a very large number of plays, not a promise for one session. A 96% RTP means a 4% house edge on average