How to setup Google Voice as Voicemail on Samsung Galaxy S21

The old method of setting up a phone to use google voice voicemail appears to be over, at least for AT&T and and Galaxy S21.

Old method:
Call forward if unanswered: *61*1234567890#
Call forward if unreachable: *62*1234567890#
Call forward if busy: *67*1234567890#

It actually didn't stop working but it did get extremely unreliable, sometimes working, sometimes giving the caller nothing.

What actually worked:
On the Galaxy S21 goto Call app > Settings > Supplementary Services > Call Forwarding

Then enter your google voice number for the following items:

Forward when busy

Forward when unanswered

Forward when unreachable