I need help with adding a skip stage feature to my obby?

Im new to scripting and I'm trying to make an obby. I've found plenty of fms for an obby that saves your checkpoints with datastore/leaderstats and plenty of fms for an obby that lets you skip stages with devproducts. But I have yet to find one with both.

So basically I could use some help. Here are my scripts so far.

obbyhandler:

local obbyStages = workspace:WaitForChild("Checkpoints")

for _,stage in pairs(obbyStages:GetChildren()) do
	stage.Touched:connect(function(hit)
		local hum
		if hit.Parent:FindFirstChild("Humanoid") then
			hum = hit.Parent.Humanoid
		end
		if hit.Parent and hit.Parent.Parent:FindFirstChild("Humanoid") then
			hum = hit.Parent.Parent.Humanoid
		end
		if hum then
				local plr = game.Players:GetPlayerFromCharacter(hum.Parent)	
				local plrStage = plr.leaderstats.Stage.Value
				if tonumber(stage.Name) == plrStage + 1 then
					plr.leaderstats.Stage.Value = plr.leaderstats.Stage.Value + 1
				elseif tonumber(stage.Name) > plrStage + 1 then
					hum.Health = 0
				end
		end
	end)
end

playerhandler:

local player = game:GetService("Players")
local dataStoreService = game:GetService("DataStoreService")
local saveDataStore = dataStoreService:GetDataStore("SaveDataTest")

local function savePlrData(plr)
	local success,err = pcall(function()
		local saveData = {}	
		for _,stat in pairs(plr.leaderstats:GetChildren())do
			saveData[stat.Name] = stat.Value
		end
		saveDataStore:SetAsync(plr.UserId,saveData)
	end)
	if not success then return err end
end

player.PlayerAdded:connect(function(plr)
	local stats = Instance.new("Folder")
	stats.Name = "leaderstats"
	stats.Parent = plr
	local stage = Instance.new("IntValue")
	stage.Name = "Stage"
	stage.Parent = stats
	local data = saveDataStore:GetAsync(plr.UserId)

	if data then
		print(data.Stage)	
		for _,stat in pairs(stats:GetChildren()) do
			stat.Value = data[stat.Name]	
	end	
	else
		print(plr.Name .. " has no data")
	end
	plr.CharacterAdded:connect(function(char)
	
		local humanoid,hrp = char:WaitForChild("Humanoid"),char:WaitForChild("HumanoidRootPart")
		wait()
		if humanoid and hrp then
			if stage.Value ~= 0 then
				local part = workspace.Checkpoints:FindFirstChild(stage.Value)
				hrp.CFrame = part.CFrame + Vector3.new(0,1,0)
			end
   		end
	end)
end)

player.PlayerRemoving:connect(function(plr)
	local err = savePlrData(plr)
	if err then print(err) end
end)

game:BindToClose(function()
	for _,plr in pairs(player:GetPlayers()) do
		local err = savePlrData(plr)
		if err then print(err) end
	end
	wait(2)
end)

All of that is for the handling and datastore (and it works great). I just don't know how to incorporate a skip stage feature. I've already got this for a button that allows purchasing a skip.

local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players") 
local productID = 1049036924 

script.Parent.MouseButton1Click:Connect(function(promptPurchase)
	local player = Players.LocalPlayer
	MarketplaceService:PromptProductPurchase(player, productID)
end)

Finally, I have used numerous tutorials but haven't figured out how to do it. The closest I got was the devproduct purchase prompt appearing, me buying it, nothing happening except the output telling me the datastore has too many requests.

That's all folks. I know its a lot (at least i think it is) so i cant say I expect a lot of help, but a forum post is worth a shot.