How would I save data using JSONEncode?

I am trying to make a datastore that stores many values and I have been told to use JSONEnocde and Decode. I have the data in a table which the data is gained from replicatedStorage. I then JSONEncode the table and then save the encoded data. I then decode the data using JSONDecode once they enter back in the game and set the values of the replicatedStorage to the table that was decoded. I use a pcall function and get the error when I save and load data. If using this method is inefficent just let me know. Ideas?

--Get The Service's
local replicatedStorage = game:GetService("ReplicatedStorage")
local timePlayedValue = replicatedStorage.PlayerStats:WaitForChild("TimePlayedValue")
local totalTimeValue = replicatedStorage.PlayerStats:WaitForChild("TotalTimeValue")
local httpsService = game:GetService("HttpService")
local dsService = game:GetService("DataStoreService")
local mainStore = dsService:GetDataStore("MainDataStore")

--Get The Gameplay Stats
local CompletedMissionsValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("CompletedMissionsValue")
local FailedMissionsValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("FailedMissionsValue")
local PreviousMissionValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("PreviousMissionValue")
local TimesDiedValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("TimesDiedValue")
local TrapsAvoidedValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("TrapsAvoidedValue")
local TrapsFailedValue = game:GetService("ReplicatedStorage").GamePlayStats:WaitForChild("TrapsFailedValue")

--Get The PlayerStats
local CoinsValue = replicatedStorage.PlayerStats:WaitForChild("Coins")
local DateFirstJoinedValue = replicatedStorage.PlayerStats:WaitForChild("DateFirstJoinedValue")
local RankValue = replicatedStorage.PlayerStats:WaitForChild("Rank")
local ExperienceValue = replicatedStorage.PlayerStats:WaitForChild("XP")

--Table To Store Data
local AllStatsTable = {
	CompletedMissionsValue.Value,FailedMissionsValue.Value,PreviousMissionValue.Value,TimesDiedValue.Value,TrapsAvoidedValue.Value,TrapsFailedValue.Value,
	CoinsValue.Value,DateFirstJoinedValue.Value,RankValue.Value,ExperienceValue.Value,totalTimeValue.Value
}

--Increment Time Values
incrementor = coroutine.create(function()
	while wait(1) do
		timePlayedValue.Value = timePlayedValue.Value + 1
		totalTimeValue.Value = totalTimeValue.Value + 1
	end
end)

coroutine.resume(incrementor)

game:GetService("Players").PlayerRemoving:Connect(function(player)
	local err,success = pcall(function()
		local jsonTable = httpsService:JSONEncode(AllStatsTable)
		mainStore:SetAsync(player.UserId,jsonTable)
	end)
	if err then
		print("error saving")
	end
end)

game:GetService("Players").PlayerAdded:Connect(function(player)
	local err,success = pcall(function()
		local jsonTable = mainStore:GetAsync(player.UserId)
		local data = httpsService:JSONDecode(jsonTable) 
		if data then
			print("data avaliable")
			data[1] = AllStatsTable[1]
		end
		
	end)
	if err then
		print("error loading")
	end
end)

You don't need to use JSON encoding to use datastores, they do that automatically when you read/write to them. All you need is mainStore:GetAsync(key) and mainStore:SetAsync(key, value)