Most hours spent on one game?

Counter Strike Global Offensive. It was rough times.

i thinkmy most played games were fivem and csgo +1000h each

3k hours in Arma3, from when Roleplay in Arma was really big

900 hours in counter strike global offensive

That's by far Garry's Mod with 6797 hours

my post played game on steam is GMOD i would play that game hours at a time, i think im at like 900 hours, ik thats not much but to me it is considering i made my steam account in 2017

Mine is Garry's Mod with over 2k hours, I was really into MilitaryRP and Clone Wars RP when I was younger

World of Warcraft, best years of my life :D but I don't regret it (often)

I've easily spent years combined playing Runescape.

easily that i have played the most would be dead by daylight or overwatch.