iPhone focus will not block whatsapp calls

Hello,

I'm trying to use a focus mode (existing or custom) to allow all normal calls but nothing else, including no whatsapp calls.

For some reason this does not work, I was doing it in an old phone that has iOS 15.8.2 and won't update further, but even the latest 17.4.1 on my iPhone 14 doesn't seem to offer this option...

Is this a bug, a "feature", or I am setting it up wrong?

I am allowing calls from everyone (under People) and allow only Phone (under apps). What else do I have to do?

Is it considering the whatsapp call the same as a normal call and thus allowing it because I have "allow calls from everyone"??