Ways of using ingame default inventory gui and such?

Is there a way of getting the position of the default player inventory in a game? I want to base the position of my stamina bar off of it, otherwise, how can I make sure that the stamina gui stays in the same place on different screen sizes(probably not for mobile yet, but if you could lmk how that work that would be really helpful!). I just figure if you can disable the default player inventory like below, there might be a way to add onto it without just being able to disable it.

game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.All, false)