I might dump 20W50 into an old worn out oil burner without hydraulic lifters or variable valve timing. Otherwise this sounds like trouble.
GM is probably the best about having interchangeable parts. I don’t know about the last 10 years or so but the older models were certainly good about that. They were the masters of badge engineering for a while. Again, you have the same basic parts but they call for a different oil viscosity. Strange…
Although engines have changed, oils have also changed. Thinner oils protect better and there is no way you could have protected and engine with 0W(anything) in the old days. Now it is quite common. A 0W40 might be about as close to a universal oil as you can get.
I run that Rotella T6 5W40 in all of my mowers and most of them originally called for 10W30. I have to say those engines seem to hold up better since that change. I do tend to run them quite hard and show them no mercy and the oil seems to hold up quite well. I am always amazed that it doesn’t look more broken down when I change it each season and I put a lot of hours of hard use on those engines. This is a full synthetic which helps withstand the high heat and stresses of an air-cooled engine.