I should have posted this update sooner but after a few weeks of troubleshooting, I determined the issue was with my router. The main isolation was playing the game on macOS and experiencing the issue with an entirely different config. I had also created new characters on different servers and still encountered the issue. Nobody in my FC or friends circle was experiencing these DCs during play, so a Square server issue seemed unlikely. No other internet connectivity issues at my location. After replacing the [practically 10 year old] router with a modern, gaming-focused router from Asus - I've never seen another 90006 error on either PS4 or macOS.
