Off campus rent and food are eligible expenses for a 529 distribution, but the amount is limited to the lesser of your actual cost or the schools "allowance for cost of attendance" (COA) for financial aid purposes. Although COA is basically, and usually, what the school charges on campus students for Room and board, you can't use that in an unclear situation, like yours. The COA is usually published by the school and on the web site.
See this off campus explanation:
https://www.glassjacobson.com/blog/529-off-campus-housing/
In most off campus situations, the COA is going to govern. That said, your actual costs would have to be prorated, for the actual time school was in session, e.g. you don't get to claim rent for all of May if graduation is May 5 2026.
