Following these steps, I've been able to run a script to log in to a web app I'm testing on Microsoft Edge using Groovy in a JSR223 Sampler in JMeter. My script clicks on a "Sign In" button, which then automatically signs me in (presumably through my credentials used to sign into my computer*). However, this test case should be able to log in as multiple users, so having me automatically sign in with my credentials isn't the intended use case. Through some trial-and-error, I found that I don't get automatically signed in when using the web app in Edge either (a) with inPrivate mode or (b) with a Guest account. Using either one of these approaches seems the most intuitive way to resolve this issue, but I am not sure if there's a way to do either (or both) of them in JMeter.
*It's a company laptop and I can't log in as a local user.