Upgrade to New Architecture - HomePods Not Working

My HomePods (on 18.2) no longer present any controls or access from the Home app on my iPhone, and I see a message instructing me to upgrade my home architecture. Following the instructions I've found online, I go into my Home settings and go to Software Update, however I'm informed after a short wait that all of my devices are up to date. Not sure how to address this at this point.