Passkeys on one Apple iPhone device showing for some Apple IDs but not for other Apple IDs

Why are Passkeys on one Apple iPhone device showing for some Apple IDs but not for other Apple IDs When trying to login to iCloud.com On iPhone which is running iOS 18.3.2 (latest currently), the option to create and then use passkeys shows up for some Apple IDs, while it does not appear for other Apple IDs on the same iPhone. This is not as per Apple support Articles. https://support.apple.com/en-in/guide/iphone/iphf538ea8d0/ios To explain my problem in detail: I have three Apple IDs, but I get option to create & use passkeys for only one Apple ID. For the second Apple ID, I get no button of Use Passkeys upon login screen. For the third Apple ID, the Use passkeys button appears on login screen, but upon clicking it the option to use passkeys for first Apple ID appears without allowing to create a new passkey for the third Apple ID. iCloud Keychain and TFA are both turned on for all the iCloud accounts. I have tried to login to the each of the Apple IDs on the same iPhone. Yet irrespective of the Apple ID used to login on the iPhone, the option for passkeys does not appear for any Apple ID except the first Apple ID. How to ensure option for passkeys shows up for all Apple IDs.