Everyone will need a phone number at some point. How one should obtain and use phone numbers in a private/secure way?
You could buy a pre-paid SIM with cash, if that’s an option.
This is correct, but for most of us we will eventually to link it to other personally identifiable information. That’s life in the modern world.
You might need more than one number if you want to communicate privately by phone knowing you’re other number is compromised by your bank, employer, credit card company, etc.
Buy more pre-paid SIMs with cash.