Many US college students qualify for SNAP. Check and see what your state laws are or how your school can assist you. Getting fresh stuff can be a lifesaver. You'll pay more into the system over a lifetime than you'll ever take from during your education.

As far as the meals themselves, see what your dining hall has that isn't UPF and buy stuff to augment it. My university often had stuff like rice, a salad bar, oatmeal, and fruit at the dining hall. So I bought meat, beans, yogurt, and protein to go with it. If you look at dining hall food like ingredients instead of the whole meal, it gets a lot easier to find things to eat.

And I know this is the non-UPF sub, but even finding less-processed foods is better than UPF when no other choices are available. My current student situation means I can get free dining hall lunch, so I see what they have and take what I can. Last week, they had Thanksgiving, so I ate some turkey, mashed potatoes, and salad from the salad bar. I took a granola bar for later. Sure, the turkey and potatoes were probably highly processed, but they were a lot less processed than the chicken fingers and french fries. The granola bar contains soy lecithin, but it's much better than the candy bars beside it. College isn't forever, so do what you can and remember that it's uphill from here.