RTP and house edge describe the long-run maths, not a promise about one...
https://kilo-wiki.win/index.php/How_Do_I_Estimate_the_Cost_of_a_Casino_Session_Before_I_Play%3F
RTP and house edge describe the long-run maths, not a promise about one session: a 96% RTP means a 4% house edge on average over many plays