iOS 26 can sort-of do what you suggest in your second paragraph. The device answers the call, asks who is calling and the purpose of the call, then (if the caller doesn’t hang up) presents the answers textually in the call-answering UI to allow you to decide whether to answer or not.

At the moment, most spam callers just hang up so I never even get to the choice to answer, although I do wonder if that’ll change if the feature gets popular.