On Steam… CS2 + CS:GO is probably at the top. I used to compete in league play. Practice, scrims, and matches and all that.

2nd is CS:S despite my last real session being 12 years ago, but that may be soon toppled by Elden Ring or 7 Days to Die.

Who knows how much time I’ve spent in LoL or WoW but I’m sure it’s in the “several thousand hours” magnitude for each.