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)