My D’s school is 2 hours. It’s not so much the length of time but start and end times.
Personally I think dining times should be 3 hours minimum. If they expanded the hours it might also help alleviate the hour long wait times. But the labor shortages are clearly contributing if the schools can’t even staff all the dining halls adequately.
One option might be to convert some of the meal swipes to dollars that can be spent outside traditional dining halls either on or off campus. Could end up cheaper for the schools because they won’t have to hire as many workers.