I’ve been running the developer beta of iOS14 since a few days in and it appears to have broken my Siri integration. The Home app is fine, and using control centre Home favourites it’s fine, but requesting Siri to do anything results in “Sorry, I wasn’t able to find anything like that in your Home this time.”
I’ve also reinstalled HA on a RPi (it’s so much faster now! - I had been running in VirtualBox for a year or so) and get the same results.
Other devices in the house running iOS13 are working as expected.
Edit. An AppleTV is my Homekit hub. It’s running tvOS13.