Why does one NGINX worker take all the load?

Scaling up TCP servers is usually straightforward, with deployments starting by using a single process setup and adding more worker processes as needed. However, increasing the number of worker processes can open up a new set of problems, and there are different ways to design a TCP server with regards to performance, including using a single listen socket and single worker process, a single listen socket and multiple worker processes, or multiple worker processes with separate listen sockets.