HomeKit

Thanks for joining Apple Support Communities, Sva1301!
I love trying all of the new things when Apple releases a brand new iOS. It looks like your Home app isn't progressing past the "loading" page though. I'll be happy to help!
1. Force an app to close on your iPhone, iPad, or iPod touch -- Forcing an app to close that isn't proceeding the way it's meant to will usually set things right again.
2. Restart your iPhone, iPad, or iPod touch -- Restarting your phone is the next step if the previous hasn't worked. A forced restart isn't called for in your situation.
Cheers!

I haven't been able to fix this in a year with multiple resets of keychain etc. they need a delete settings again

Force closing the app doesn't work and neither does restarting. Signing out of iCloud fixes the problem, but as soon as you sign back into iCloud and open the app again it goes back to "Loading Accessories and Screens."

The problem appears to be that iCloud HomeKit information is corrupt or something.

Definitely, but with no way to fix it. And it is such a hassle to try:

1) On pre-ios 10, reset home-kit in settings on all devices

2) Sign out of keychain on all devices (losing all your apple pay cards, etc.)

3) Sign out of icloud on all devices

4) Reboot all devices

5) Sign back into icloud (some also have you sign into another account, reboot, sign out, sign into your main account to clear everything) on all devices

6) sign back into keychain, and approve on all devices

7) See it all be exactly the same. 😟