I have a similar issue with one of the Five Guys in my state. It's a 2 hour drive one way, and there doesn't seem to be anyone but me or my son that is willing to go shopping in that area without giant bonus'. Someone does a few of the gas stations in that area long after the big bonus' come out, but no one is jumping and running for the Five Guys or any of the other shops the same MSC contracts.
It seems that they can't keep a full staff, at the beginning of the pandemic they shut down and only took orders outside and to go. Then they started cutting hours, and the food got bad. For a very long time they said they couldn't get the staffing and they were closing every day at 4 pm. Then a couple months ago they were magically open until 10 pm like the door says, so I went ahead and scheduled a second shop this month while I was in the area doing gas stations, and when I arrived promptly at 5 pm, there was a paper sign on the door saying that they closed at 4 pm. I did call, but I didn't ask about their closing time, I just asked if they were open, my mistake.