Did dupe glitch on minecraft server 1.21.11 didn't exist anymore?

recently i join this minecraft server. this server really good but its p2w. i wanted to try dupe glitch on this server but i can't, i already try bunch of dupe glitch from youtube claiming works on 1.21.11 but all of them not working on this server. so i was wondering, did dupe glitch doesn't exist on 1.21.11?