I own a mk6 GTI like you with the same engine. Mine is a 2013 and has a manual transmission. Mine has 142K on it. My wife uses it on her business travels a lot.
I think you got bad info regarding VW and low ash oil for your car.
If I were you, I would replace that timing chain tensioner with the latest revised one ASAP. That is the weak point on the earlier MK6 GTI's and no oil on earth will help with the earlier tensioner design flaw.
You live in Michigan and most likely near a Meijer store. Look for a 5 qt jug of Valvoline 0W40 or 5W40 at Meijer. The 5W40 is a mid saps oil while the 0W40 is a full saps formulation. Both are VW 502 oils.
If you want a low ash oil, look for something that is VW 504/507.
BTW, the intake manifold on my GTI went out around 82K. I cleaned the intake valves and injector tips while I was at it.
The on engine mechanical fuel pump gave out while my wife was far from home. Easy to replace. The car can run on the in tank fuel pump but you lose a lot of power.
The oil separator gave out once. If that goes out, STOP DRIVING your car and have it towed and replace it. Unless you wanna pop the rear main seal and add another $1000.00
to the repair bill.
The dual mass flywheel gave out at 50K. Right after my wife got back from seeing her parents in NYC, which murdered it.
Could of had it replaced free under warranty. Figured deal with it on my dime now and make it reliable with a traditional flywheel, new clutch and throwout bearing.
There are two water pumps on these cars. One is electric that sometimes runs when you shut the car off. The electric unit is known to fail, but mine hasn't yet.
Again, the timing chain tensioner is something I would replace if I owned your car.
Ignition coils weren't very reliable but they are cheap to replace with the latest revised part number. In fact, I'd replace them now to have piece of mind, carry a spare in the spare tire well and carry one of those blue tooth code readers. When my wife broke down far from home, she plugged in the code reader and I determined it was most likely the fuel pump which it was, a dealer had it in stock and I got her going again.
ECS Tuning is a good source of genuine and quality aftermarket VW parts.
This Youtube channel has many videos on VW TSI engine repairs like replacing the intake manifold and oil separator.