Getting Home Assistant to play nicely with Google without using their Nabu Casa service definitely is a hurdle, but once you get over it, it’s super nice. I ended up just blocking Google DNS inside my network to force all the Google home devices to use my internal DNS to fix the https/hairpin NAT issue. It wasn’t a big deal since my kids are getting older and I needed to block outbound DNS in general since they’re getting savvy enough to get around my content filtering.