That auto-opt in for alternate route is the worst feature ever.
I've had cases where I was on a highway far away from any exits and there was a jam caused by an accident, and google maps started flip flopping between 2 different "optimal" routes that required me to first take one exit that's ahead of me, and then another exit that was far behind me. Presumably google was seeing the traffic jam and determined that my current route is no longer optimal, and wanted me to do a U Turn on a highway where there are no exits.
Apple Maps will suggest alternate routes with an automatic opt-in if you don't respond, but, in my experience, it's much more conservative about making those suggestions.
I've had cases where I was on a highway far away from any exits and there was a jam caused by an accident, and google maps started flip flopping between 2 different "optimal" routes that required me to first take one exit that's ahead of me, and then another exit that was far behind me. Presumably google was seeing the traffic jam and determined that my current route is no longer optimal, and wanted me to do a U Turn on a highway where there are no exits.