One way around this is to press TO/GA, followed by FLCH. If done without too much pause, the Approach mode will terminate, the thrust levers will advance slightly, then reduce to a low setting compatible with the remaining descent altitude and the aircraft will continue descent to the MAP alt.
I haven’t heard that before but I guess it would work.
You can do it nicely by retuning the Nav receivers and then engaging V/s and whatever lateral mode you think is best at the time.