RTP is a game’s theoretical average return over a very large number of plays,...

https://www.jelly-bookmarks.win/rtp-estimates-long-run-returns-the-house-edge-is-the-casino-s-average-share

RTP is a game’s theoretical average return over a very large number of plays, while the house edge is the share the game is expected to keep. For example, 96% RTP = 4% house edge