Thank you, @crooked-zebra-94702. I am trying to transition away from GitHub Actions. There I used someone's GitHub repo (wait-for-netlify-action) as a customized step for the wait action but I think that was GitHub Actions specific. Not sure if that's needed with Circle CI.
Probably not what you're looking for but wonder if you use cy.intercept to get network requests and add cy.wait for specific time periods to simulate the network speeds you want. That'd be great if there was a network speed paramter.