For a large public school, how will admissions be different for full pay OOS students? I am thinking of schools like Penn State and Wisconsin. Will full pay out of state applicants get a boost?
I do not think that we know. Any prediction would be only a guess.
One possible guess: The economic uncertainly caused by the COVID pandemic will cause more students to apply to and prefer in-state public universities. This might or might not improve your chances as a full pay out of state student.
However, all that you can do is to apply, make sure that you apply to at least two safeties, and see how you do.