Problems Open Access founders encounter in their go-to-market strategy

I have experience in go-to-market but no direct experience selling Open Access products. I'd love to learn from founders in this space what actually breaks (or works) in your GTM journey when you try to commercialize.

What's your product (OA publishing, data, APIs, infra)?

Who actually pays, if the end user doesn't? Biggest GTM surprise so far? How did you land your first paying customer? Where does your sales cycle stall the most? Most common objection you hear? What channel has actually worked for you?