After working for a while and even working this morning, my Apple Watch now says devices are not responding. However, my Mac and my iPhone are still working if I use Siri to turn on/off anything. HomeKit certified devices (Lutron Caseta with Pro Hub and my Ecobees) still work from the Apple Watch. The only difference between this morning when everything was working and now is my MyQ garage doors are unavailable in HA.
My theory, and so far this has been true the past few times my watch doesn’t work, is if even a single device from HA is unavailable or not responding in HomeKit, the Apple Watch thinks all devices paired through HA are not responding. If I remove the MyQ garage doors which are currently unavailable and reload HomeKit, the watch starts working again.