Drill mode, speed 1, don’t push.
From what I’ve gathered online, your drill has UP TO 750lbs of torque. For an 8” auger, 750lbs should be minimum. Sounds like your drill is working too hard, overheating, and shutting off so your motor doesn’t fry especially since you say it does it 1-2 times per hole. Have you tried a smaller auger bit? An 8” hole removes twice as much ice as a 6” hole. I bet a 6” would run a lot better.
Hopefully someone will come along that uses that drill and has something more to say.