I use a Chinese Android phone called OPPO R17 Pro, and I have exactly this feature built into the stock-rom (ColorOS) and a bunch of other really cool once, suc

I use a Chinese Android phone called OPPO R17 Pro, and I have exactly this feature built into the stock-rom (ColorOS) and a bunch of other really cool once, such as block foreign numbers, numbers not in my contact list, numbers not on my VIP-list, service numbers etc.