I just bought a Macbook Pro 2019 refurb and am having this same issue. I got this one on the advice of the apple sales guy as he said it is more than capable of running Swift Playgrounds but 5/10 minutes in to using the app it sounds like it's about to take off. I spoke to a Tech advisor last week who said it definitely shouldn't do that and arranged for a replacement macbook to be sent out which arrived yesterday, and it's doing the exact same thing... Mine is the Macbook Pro 2019, 8gb, 256gb SSD.. App runs flawlessly on my iPad Air 2 so seems strange to me that a Macbook Pro struggles with it?