Hi, Welcome to the forum!
Sounds like your cam chain and tensioner are worn, makes the car sound like a diesel! similar to what mine sounded like when i first got it, there are loads of topics on here about it, its not a massive job I paid around £120 for the tensioner and chain from vw and you're looking at around 4 hrs labour.
The problem is sometimes the camshaft adjuster can be worn too or gets damaged trying to remove it as the bolt holding it on is ft! and this is expensive, around £300 iirc, i read many posts where people didnt change it and the rattle was still there, I opted not to change it on mine and it was fine after so its up to you, read about it as much as you can to decide.
It is also a wise choice to change the cam follower too if you have no record of it being done recently.
