[noman-land]

If your adversary is a nation state, hiding your phone number is not an option. They already know it and might compromise a device. Perhaps another service is better or the use of a burner phone is preferred.

[joemazerino]

How can a nation-state adversary compromise a device only knowing the phone number?

[ncmncm]

1. Track locations of phones in contact.

2. Rubber hose.

3. Obtain copies of your messages still retained in your contacts' phones.