RTP shows how much a slot pays back over time, but volatility tells you how...

https://page-wiki.win/index.php/How_Are_Online_Slots_Tested_for_Fairness%3F_The_Truth_Behind_the_Spinning_Reels

RTP shows how much a slot pays back over time, but volatility tells you how wild those wins can get. Good platforms back these numbers with independent RNG tests, so you know the bonus rounds aren’t just smoke and mirrors