Not a lawyer (yeah yeah I know) but am an accountant with plenty of education & experience in business law, taxes, and business formation (incl nonprofits). So I can't really give formal legal advice but research and filling out paperwork is literally my specialty.

I will say that "formally structuring" this website as literally anything besides a website sure does complicate things in a big way, idk how much the donations are bringing in but it's a whole thing. The first thing anyone says about forming a "business" (including a nonprofit) is you need a lawyer and an accountant so I'm just throwing that out there