why are my leaderboard remote functions not working?

I am making a game and want to make a power up shop that can affect all players and reset after a certain amount of time similar to Toh. Here are the scripts i have at the moment

inside the button

script.Parent.MouseButton1Click:Connect(function(player)
	game.ReplicatedStorage.PowerUps.Gravity:FireServer()
end)

leaderstats

local function onPlayerJoin(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player
 
	-- Display an 'IntValue' on leaderboard
	local gold = Instance.new("IntValue")
	gold.Name = "Gold"
	gold.Value = 0
	gold.Parent = leaderstats
end
 
game.Players.PlayerAdded:Connect(onPlayerJoin)

and the gravity function

game.ReplicatedStorage.PowerUps.Gravity.OnServerEvent:Connect(function(player)
	if player.leaderstats.cash.value >= 10 then
		player.leaderstats.cash.value = player.leaderstats.cash.value - 10
		game.Workspace.Gravity = 90
	end
end)

My output keeps saying leaderstats is not a valid member of player