Using DataStore2 To set default value?

Try doing this instead:

function UpdateLevel(GetData)
    Level.Value = LevelStore:Get(DefaultLevel)
end

This will automatically get the data of the player plus the default value will be considered the default, as long as LevelStore is the datastore that is defined by:

LevelStore = DataStore2("LevelStore", player) -- player must be a player instance

You don't need anything else. Hope this helps!

I made this its still not working

local Rep = game:GetService("ReplicatedStorage")
local DataStore2 = require(Rep:WaitForChild("MainModule"))

DataStore2.Combine("DataStoreOPM", "Level", "Points", "Exp", "MaxExp", "Strength", "Health", "Agility", "Money")

-- Defaults
local DefaultLevel  = 1

local DefaultMaxExp = 50
local DefaultExp = 0
local DefaultPoints = 0

local DefaultStrength = 1 
local DefaultHealth = 1
local DefaultAgility = 1

local DefaultMoney = 200

game.Players.PlayerAdded:Connect(function(player)

    -- Store the values

    local LevelStore = DataStore2("Level",player)
    local ExpStore = DataStore2("Exp",player)
    local MaxExpStore = DataStore2("MaxExp", player)
    local StorePoints = DataStore2("Points", player)

    local StrengthStore = DataStore2("Strength",player)
    local HealthStore = DataStore2("Health",player)
    local AgilityStore = DataStore2("Agility",player)
    local MoneyStore = DataStore2("Money",player)

    -- Leaderstats
    local Data = Instance.new("Folder", player)
    Data.Name = "Data"

    local Level = Instance.new("IntValue", Data)
    Level.Name = "Level"

    local Exp = Instance.new("IntValue", Data)
    Exp.Name = "Exp"

    local MaxExp = Instance.new("IntValue", Data)
    MaxExp.Name = "MaxExp"
    MaxExp.Value = (player.Data.Level.Value + 1 ) * 1.25 *( 50)

    local Points = Instance.new("IntValue", Data)
    Points.Name = "Points"

    local Strength = Instance.new("IntValue", Data)
    Strength.Name = "Strength"

    local Health = Instance.new("IntValue", Data)
    Health.Name = "Health"

    local Agility = Instance.new("IntValue", Data)
    Agility.Name = "Agility"

    local Money = Instance.new("IntValue", Data)
    Money.Name = "Money"

        print("OnGoing")
    if player.Data.Level.Value < DefaultLevel then
        print("Test")
            LevelStore:Get(DefaultLevel)
            print("Yes")
            wait(2)
        end


    --  Update Functions

    local function UpdateLevel(GetData)
        Level.Value = LevelStore:Get(DefaultLevel)
    end

    local function UpdateExp(GetData)
        Exp.Value = ExpStore:Get(GetData)
    end

    local function UpdateMaxExp(GetData)
        MaxExp.Value = MaxExpStore:Get(GetData)
    end

    local function UpdatePoints(GetData)
        Points.Value = StorePoints:Get(GetData)
    end

    local function UpdateStrength(GetData)
        Strength.Value = StrengthStore:Get(GetData)
    end

    local function UpdateHealth(GetData)
        Health.Value = HealthStore:Get(GetData)
    end

    local function AgilityUpdate(GetData)
        Agility.Value = AgilityStore:Get(GetData)
    end

    local function MoneyUpdate(GetData)
        Money.Value = MoneyStore:Get(GetData)
    end

    -- Setting the functions here 
    UpdateExp()
    UpdateHealth()
    UpdateLevel()
    UpdateMaxExp()
    UpdatePoints()
    UpdateStrength()
    AgilityUpdate()
    MoneyUpdate()

    -- If the data update then save it

    ExpStore:OnUpdate(UpdateExp)
    HealthStore:OnUpdate(UpdateHealth)
    LevelStore:OnUpdate(UpdateLevel)
    StorePoints:OnUpdate(UpdatePoints)
    StrengthStore:OnUpdate(UpdateStrength)
    MoneyStore:OnUpdate(MoneyUpdate)
    AgilityStore:OnUpdate(AgilityUpdate)
    MaxExpStore:OnUpdate(UpdateMaxExp)

end)