The SMC reset didn't work; neither did other procedures Apple tried; and software updates didn't stop it either. The only thing that helps is keeping it on top of a cake cooling rack.
So I think One Green Bottle must be right when he says he thinks the problem is a design flaw in the hardware itself. That being the case, then all other 2020 MacBook Pro laptops will have the same flaw. So, if I return it and exchange it for a new one, I will have the same problem with the new one.
I'm glad that the Apple stores were closed in my city because of the Pandemic, so I wasn't able to bring it in to them to try and fix it. Now I realize the problem cannot be fixed, just mitigated by the use of devices to cool the laptop from underneath it - whether passive ones, such as my cake cooling rack, or active interventions such as the laptop stand with built in fans used to cool the laptop.