We actually do look at network requests, but we only do this to assess page-load. Assessing this is a surprisingly hard-problem.

I don't think our UI Testing tools monitor network traffic though. I can see how that might recur - if you email a test scenario to (my HN name) AT axiom.ai, we may be able to whip up some JS, that could be turned into a no-code block, for you and others to use.