One other quick post ... went to get gas Tuesday evening. I always have the keyless entry fob in my pocket. Usually, when I get gas, the car doesn't tend to lock itself until I pop open the cap and go to the pump since I'm still close enough to the car. This time, though, I must have walked far enough around it that the car locked itself. I couldn't get the gas "door" open and started to panic .. thoought it was broke, thought I was going to have to try to pry it open and ruin it, or ruin the paint, or both .. then thankfully dawned on me that maybe the gas door locks when the car does.
Sure enough, I hit the unlock button on the fob and the gas door opens. So .. for any other dorks/noobs like me, know that your automatic locks also lock the gas door on your Regal Sportback, or at least they do on my 2018 model. : )