I'm of the opinion that you have nothing to report on your taxes. The foundation is simply funding the expenses. It's essentially an "accountable reimbursement plan".
I based that opinion on your own description of the funding:
"I did not receive a 1099-NEC, or any other tax form. If it were a business, I could easily deduct all the expenses and have no income left over. Whatever I will end up not using, I will have to return at the end."
"Instead, I use them for activities such as buying data, supplies, to pay for research assistants, and make other research expenses (conference registration fees, etc). I need to maintain a list of such expenditures, and submit them to the foundation supporting my research at the end."
"Importantly, these aren't compensation for teaching/research as a graduate student (that's the scholarship I first mentioned)."
