My income is around 300k, so I doubt I will qualify for any financial aid. It costs $16 per school to send the CSS profile, and I applied to many schools. Should I submit my CSS profile or even apply for financial aid in general?
Only if the college requires it to be considered for merit aid (very few would, but check the scholarship section of the college website). Some colleges also have rules about not being able to apply for aid in future years if you don’t apply as a frosh. But your folks likely have hefty savings, so odds of you needing to do that are slim. I’d skip it.
There are a handful of schools that place restrictions on applying for aid in subsequent years for U.S. citizens. There are a LOT that place restrictions for international students.