Trying to make a DataStore, but it doesn't appear to save the data. What is wrong with my script?

I have it so that when a player leaves it creates a table with their data, and when they join it retrieves that data, but if they have no data it sets a default value. But it doesn't seem to save the data because when you join, it just sets it to the default value no matter what

script:

 
local Players = game:GetService("Players")

local DataStoreService = game:GetService("DataStoreService")
local PlayerData = DataStoreService:GetDataStore("TestDataV1")


Players.PlayerAdded:Connect(function(player)
	local Data;
	
	local DataFetchSuccess,ErrorMessage = pcall(function()
		Data = PlayerData:GetAsync(player.UserId)
	end)
	
	if not DataFetchSuccess then
		player:Kick("Unable to load your data, please rejoin.")
		return
	end
	
	local Stats = Instance.new("Folder")
	Stats.Name = "Stats"
	
	local Cash = Instance.new("IntValue", Stats)
	Cash.Name = "Cash"
	
	local Stars = Instance.new("IntValue", Stats)
	Stars.Name = "Stars"
	
	Stats.Parent = player

	if Data then
		Cash.Value = Data.Cash
		Stars.Value = Data.Stars
	else
		Cash.Value = 100
		Stars.Value = 5
	end
end)
	

Players.PlayerRemoving:Connect(function(player)
	local Data = {
		
	}
	Data.Cash = player.Stats.Cash.Value
	Data.Stars = player.Stats.Stars.Value
	
	local DataWriteSuccess,ErrorMessage = pcall(function()
		PlayerData:SetAsync(player.UserId, Data)
	end)
	
	if not DataWriteSuccess then
		warn("Couldn't save data of "..player.Name)
	end
end)

You forgot to use DataStore:SetAsync if the player is new, so there is no data made. Instead, you should try this:

local Players = game:GetService("Players")

local DataStoreService = game:GetService("DataStoreService")
local PlayerData = DataStoreService:GetDataStore("TestDataV1")


Players.PlayerAdded:Connect(function(player)
    local Data;

    local DataFetchSuccess,ErrorMessage = pcall(function()
        Data = PlayerData:GetAsync(player.UserId)
    end)

    if not DataFetchSuccess then
        player:Kick("Unable to load your data, please rejoin.")
        return
    end

    local Stats = Instance.new("Folder")
    Stats.Name = "leaderstats"

    local Cash = Instance.new("IntValue", Stats)
    Cash.Name = "Cash"

    local Stars = Instance.new("IntValue", Stats)
    Stars.Name = "Stars"

    Stats.Parent = player

    if Data then
        Cash.Value = Data.Cash
        Stars.Value = Data.Stars
	else -- Data doesn't exist
		local DefaultValues = {
		cash = 100,
        stars = 5
		}
		PlayerData:SetAsync(player.UserId, DefaultValues) -- set data store to default values
		Cash.Value = DefaultValues.cash -- set leaderstats to default values
		Stars.Value = DefaultValues.stars
    end
end)


Players.PlayerRemoving:Connect(function(player)
    local Data = {

    }
    Data.Cash = player.leaderstats.Cash.Value
    Data.Stars = player.leaderstats.Stars.Value

    local DataWriteSuccess,ErrorMessage = pcall(function()
        PlayerData:SetAsync(player.UserId, Data)
    end)

    if not DataWriteSuccess then
        warn("Couldn't save data of "..player.Name)
    end
end)

I highly recommend the "Datastore Editor" plugin by Crazyman32, it really helped me do this.