A slot at 96% RTP has a 4% house edge. That is not a fee taken off each win. It is the long-run gap between stakes and returns. One session does not land on 4%.
Blackjack can sit near 0.5% with basic strategy and rules that pay 3:2. Baccarat banker bets sit near 1.06% after the usual 5% commission. Keno and roulette sit wider. A bonus with wagering widens the edge again, because you must bet the bonus before you can withdraw it.