This was a few years ago on a 2015 MBP running Catalina or whatever came before that. My guess is the adaptive bandwidth algorithm acutely switches to a lower bandwidth due to the lag spike, and then slowly recovers in the ten seconds after. And then 50 seconds later it starts over again. I suspect if I could have manually set the streaming quality to a fixed value the lag spike would hardly not be noticable at all, but the constant switching of the stream quality is what actually caused chopiness. Same might be the case with the OP's zoom calls