Its very odd, I am trying this with Nostash and Safari browser on iOS and its working fine, login no problem. No NIP-05 just a random new key.

it would be great to see an source repository that works with Keychat and see what their settings are to compare with ours and help find the discrepancy

Yes after refreshing the page once or twice the extension is detected and allows me to log in.

But it doesn’t detect it right away for some reason.