iOS 17 comes with a voicemail transcription feature. Not sure how useful that would be since I don't even remember when was the last time I got a voicemail, everyone just hangs and sends a WhatsApp message (if anything) at least in my country.

Phone -> Silence Unknown Callers is close, it'll only let callers in your contacts ring the phone, everyone else will be sent to voicemail (and still show up in call history so you can add them as a contact easily).

https://support.apple.com/en-ca/HT207099

Also looks like you can set up external apps to maintain block lists and filter based on that rather than your address book, but nothing that would act as a concierge to prompt callers.