How do I access everyones playergui inside a server script?

So this first script is a LOCAL SCRIPT This LOCAL SCRIPT is inside a TEXTBUTTON where only certain people can see.

script.Parent.MouseButton1Click:Connect(function(plr)
	game.ReplicatedStorage.DisableBalls:FireServer(game.Players:GetPlayers())
end)

The other script is a SERVER SCRIPT And this is inside SERVER SCRIPT SERVICE This is wrong i know that but I just want to know how do i access everyones playergui inside a server script?

game.ReplicatedStorage.DisableBalls.OnServerEvent:Connect(function(player, localplayer)
	for _,v in pairs(localplayer) do
		v.PlayerGui:WaitForChild("ScreenGui").Spawn.TextButton.Text = "Disabled"
		v.PlayerGui.ScreenGui.Spawn.TextButton.LocalScript.Disabled = true
	end
end)

This was just me having a go at it

for i,plr in next, game:GetService("Players"):GetPlayers() do
local gui=plr:FindFirstChild("PlayerGui");
if(gui) then
--code here
print(plr.Name.." gui exists!");
end
end

Hope this helps!