Why is my data not storing correctly?

Hello! I've been trying to make a datastore system, but something is going wrong. Whenever I store my data, it gives a weird number. For instance, when I join the game and set up Class-D experience to 4, Security Department experience to 6, clearance level to 7, and global experience to 3 and leave, this is what it prints: 0_0_0_0_ In theory, it should print 3_7_4_6_, but it doesn't.

--[[ // Description
Manage all main Data by storing it and gathering it. Data is stored in strings and decrypted using string.split()
]]

--// Services
local DataStoreService = game:GetService("DataStoreService")
local PlayerService = game:GetService("Players")

--// Variables
local DataStoreKey = "DevelopmentStage 3/5/2022 #4" -- Change to erase or restore data (global)
local DataStore = DataStoreService:GetDataStore(DataStoreKey)

--// Logic

function FolderGatherCreate(playerModel) -- returns the folders if present, if not it creates the folders and then returns them.
	if playerModel:FindFirstChild("Data") ~= nil then -- Data folders are present
		return playerModel.Data
	else -- Data folders are not present
		--//Instancing
		local DataFolder = Instance.new("Folder")
		local TeamData = Instance.new("Folder")
		local GlobalExperience = Instance.new("IntValue")
		local KeycardClearanceLevel = Instance.new("IntValue")
		
		local ClassDFolder = Instance.new("Folder")
		local ClassDExperience = Instance.new("IntValue")
		
		local SecurityDeptFolder = Instance.new("Folder")
		local SecurityDeptExperience = Instance.new("IntValue")
		--//Properties
		DataFolder.Name = "Data"
		DataFolder.Parent  = playerModel
		
		GlobalExperience.Name = "GlobalExperience"
		GlobalExperience.Parent = DataFolder
		GlobalExperience.Value = 0
		
		KeycardClearanceLevel.Name = "ClearanceLevel"
		KeycardClearanceLevel.Parent = DataFolder
		KeycardClearanceLevel.Value = 0
		
		ClassDFolder.Name = "ClassD"
		ClassDFolder.Parent = DataFolder
		
		ClassDExperience.Name = "Experience"
		ClassDExperience.Parent = ClassDFolder
		ClassDExperience.Value = 0
		
		SecurityDeptFolder.Name = "SecurityDepartment"
		SecurityDeptFolder.Parent = DataFolder
		
		SecurityDeptExperience.Name = "Experience"
		SecurityDeptExperience.Parent = SecurityDeptFolder
		SecurityDeptExperience.Value = 0
		
		--//Misc
		return DataFolder
	end
end

PlayerService.PlayerAdded:Connect(function(playerJoined) -- Runs when a player joins the game
	--// Variables
	local playerID = playerJoined.UserId
	local DataFolder = FolderGatherCreate(playerJoined)
	
	--// Logic
	task.wait(0.1) -- Give time for Datastores to load
	
	if DataStore:GetAsync(playerID) ~= nil then
		--// Variables
		local DataGathered = DataStore:GetAsync(playerID)
		local splits = string.split(DataGathered[1],"_")
		
		--//Apply Changes
		DataFolder.GlobalExperience.Value = tonumber(splits[1])
		DataFolder.ClearanceLevel.Value = tonumber(splits[2])
		DataFolder.ClassD.Experience.Value = tonumber(splits[3])
		DataFolder.SecurityDepartment.Experience.Value = tonumber(splits[4])
	end
end)

PlayerService.PlayerRemoving:Connect(function(playerRemoved) -- Runs when a player leaves the game
	local DataFolder = FolderGatherCreate(playerRemoved)
	local StoreString = tostring(DataFolder.GlobalExperience.Value) .. "_" .. tostring(DataFolder.ClearanceLevel.Value) .. "_" .. tostring(DataFolder.ClassD.Experience.Value) .. "_" .. tostring(DataFolder.SecurityDepartment.Experience.Value) .. "_"
	print(StoreString) -- for debugging.
	DataStore:SetAsync(playerRemoved.UserId, {StoreString,true})
end)