Wow, I'm a little embarrassed that I didn't notice this earlier, but there is a Podfile.properties.json file in the ios directory of the auto-generated project I was completely unaware of until now that was overriding the jsengine as "jsc" (hence the warning indicating hermes engine was not enabled). Simply had to set "expo.jsEngine": "hermes" in that file to enable debugging with Chrome Dev Tools for the ios side of the project.