I have another home across the country with Schlage Sense locks that I created for remote control via an AppleTV that acts as a hub. Somehow the hub feature was interrupted, presumably by some combination of guests logging out of my iCloud and / or iTunes accounts on AppleTV.

Fortunately, my brother lives nearby, so I have some ability to troubleshoot. The only advice in Apple's documentation and discussion responses is to reset it as a hub by logging it back into iCloud (and one page says iTunes), making sure 2-factor authentication is turned on, and restarting the device. No combination of these steps made it appear in the Home app either remotely or on my brother's phone on the local network. We also tried to rename AppleTV and delete it via the Mac System Preferences iCloud pane and add it again. Nothing.

The home app says "Remote access not configured: Remote access setup needs to end at home where your Apple TV and iPhone are on the same wireless network", which is obviously not immediately possible. My brother was able to control devices when I added him to "people" by inviting (which I could only do while on the wifi person), but he can't add devices so he can't configure it to me. It seems that the only way for me to continue shooting problems is to take or send my phone across the country (or wait until I visit in December.)

Am I right in my assessment of this problem?

When I make it work again, it's really the case that someone who logs out of my account (so they can install an app with their own account, I suppose) eliminates my ability to access my homekit- units that are the locks for the house !? This seems like a major gap in the functionality of the system, not to mention a security issue.

I rely on this remote access to add and delete guest passwords. Is there really no way to solve this problem without flying out there myself (or being without my phone for a week while on the trip itself)? Is there any way to prevent this problem from happening again when I fix it?