Is there a way to replace the TopBar with a ScreenGui?

Is there a way to replace the TopBar with a ScreenGui and make it resize perfectly for all resolutions ?

If you want to make the topbar completely transparent you can do:

game:GetService('Players').LocalPlayer:WaitForChild('PlayerGui'):SetTopbarTransparency(0)

I recommend putting this in ReplicatedFirst, in a LocalScript.

On the other hand, if you want to replace the TopBar, you have to use a ScreenGui and position it manually.