2017 CX9 - battery issues

Hi - as the title says, I've got a 2017 Mazda CX-9 Grand Touring that is having battery trouble. We're on the 3rd battery now (replaced twice), and it died again this morning when I went to start it. There are no outstanding recalls on the vehicle.

I checked the battery voltage at rest and I got 12.89V, with the engine running it went up to 14.39V. I checked the fuses and they all seem to be good. As far as I can tell the lights and everything go off when the car shuts down. There are no open CEL's either.

I'm at my wits end here, so I would appreciate any help that the community can provide.