So, a friend has a 2020 Yukon.
Battery drain, engine dying in traffic, power steering failing, 6-7 codes .... all intermittent failures.
1st failed attempt: "It's the battery. We changed it. You are all set!"
2nd failed attempt: "It's your starter and a module. We fixed it. You are good to go!"
3rd attempt, still waiting: "It's actually the mother board. We will change that when we get one in."
Any bets the 3rd attempt will end in failure?
Most likely it is a failure.
That's the primary drawback between a real mechanic and a "Technician"
A good mechanic knows what is wrong because he knows how things work.
A technician can only read codes and take a guess. I'd tell the "Tech" that I wasn't going to pay for any work that did not solve the problem and expect a full refund for the completed "guesses" since they did not work.
That will make him lock up!
It's probably still under warranty so he's not paying anything yet.
The days of mechanics knowing how everything works is long gone. Vehicles now are too complex for that. A lot of the labour time will be be spent just diagnosing your issue, and you better believe you’re paying for it.