I'm assuming that one of the mods you has is just modifying the admin GUI badly. It's probably deleting the GUI and then creating the new one, but it was made pre V21, so it does not have the button on it.
Remove these add-ons so we can slim down on the issue1. System_GameBar2. Script_rtbingame3. GUI_tabshiftingselector4. GUI_BotWars + GameMode_BotWas5. Client_AdminGUIPlusI am pretty sure #5 is what's causing your issue.Also just a side note: Do not use Slayer with TeamDeathMatch and DefaultMinigame, they will clash heads