Source? Can't find a HN submission regarding this, and the most I found via Google is this question on the Apple developer forums https://developer.apple.com/forums/thread/127709.
This has driven me insane in 10.15.7. If my ISP has intermittent connectivity, macOS starts beach balling. To prevent this I have to shut off internet.
The catch?
Shutting down the network requires suffering through multiple beach balls. Every single mouse click or key press invokes a beach ball. Everything goes away the moment internet is connected.
It's funny because the Mac was introduced with a 1984 theme about PC as a uniform experience controlled by central authority and here we are.