Thanks for the comments.

Is there anything besides the alternator or regulator that could cause me to get only 5 to 6 volts? The reason I unhooked the battery ground was to check alternator output with my volt meter.

Diesel911, are you saying if I recharged my battery the new regulator might be fine? It's low now and I did have to jump start the car.

Also the battery is new; replaced in January 2020. OReilly tested it and said it was good. And the alternator seems to be in great shape when I look inside it with a light while the regulator is removed.