This is my first campaign DMing, and my second campaign ever, playing with 6-7 year experienced players. Everyone in our group says things are going amazingly, except one. He's voraciously consumed most d&d literature available through standards means, and is current on Drunks & Dragons, Critical Role, and TAZ. Considering our game is mostly homebrew, the backseat DMing gets a bit old. "No you roll a different save for that" "You should roll perception" "That's not the wild magic effect for that roll" The game is usually fun and I almost always have a great time running it, but having someone tell everyone how and what to roll and what to do with their characters kind of sucks. He also has the Monster Manual almost memorized so it's like "Oh well this is XXXX and is weak to XXX so Blank you should cast Suchandsuch." I just feel undermined and like I'm not creating a story that's good enough even though the other players have said it's their favorite campaign ever so far.