I don't run a business, so I don't have to worry about that (expect I'd have a separate business phone anyway). I've talked to a lot of people about this, and have seen almost universal agreement about not answering unknown numbers. My system makes life simpler, and it goes like this.....
Unknown number calls. If it's important, they leave a message. Then I call back. Immediately after the exchange, I give the number a name and add it to the contact list. If it wasn't important enough to leave a message, I dismiss it and never give it another thought. A lot of people use this same system with their personal phones.
When I advertise to the public, I specify text for first contact, but if someone calls and leaves a message, that works too.
Guess how many times I answer spam or scam calls.....Never.
How many times do I miss an important call? I don't know of any, and frankly, I don't care.
I give others the same courtesy. If I call and no one answers, I leave a message. If it's not a business and it's someone I've never called before (such as answering a CL ad), I text. If I don't get a reply to either, I move on.
Technology is great if you don't let it own you.