I am not sure I can really answer this question since I use IEMs for competitive gaming/LANs, but there is this thread on this forum that might help: (update in progress) Falenkor's Competitive Headphone Write Up. Now with added Hardware explanations!
For LANs, I would use IEMs that isolate super well and then headphones wrapped around my neck for the mic
Just another perspective, why not use your Game Zero for CSGO and then have a headphone for everything else like music/movies?