From the cited site: 1) US mostly have One party consent - which is just you 2) two party consent for some states may or may not require your phone playing anything annoying. Technically you can notify your friend while drinking beer with them that you always record phone calls, and that counts already. Nothing from Apple side is required! 3) the thing about EU and GDPR is completely irrelevant on what we are discussing - this covers businesses that record and process user data. If your phone is private and you are not recording clients call - it does not affect you.In the US it depends on which states the caller and receiver live. In the EU it's mandatory that both sides are aware of the recording.Violation can be a serious offense.
Just a random web search. https://www.vonage.com/resources/articles/call-recording-disclosure/
In summary, all cases put responsibility to user discretion, so why Apple decides instead of us? Let them just set toggle and we decide!