By "Equipping GUI", I mean the tools that it shows you have at the bottom of the screen, which you can equip.
I believe that you can't disable just the bar, you would have to disable the whole backpack GUI.
You can achieve this using the SetCoreGuiEnabled
!
-- Write this in a local script game:GetService("StarterGui"):SetCoreGuiEnabled(Enum.CoreGuiType.Backpack, false)
You can find the documentation on CoreGuiEnabled here!
You are still able to equip tools using your custom script, by parenting the tool to the player's character!