Open Collective does not accept single-maintainer projects. I tried to open an account and had an email exchange with a person there, and they told me that I'd need a second owner for the account.
I can dig up the exact wording, but there's sadly not much I can do.
No worries about digging up the wording. Thank you for your response. While I do prefer Open Collective I don't fault you for their rules. I see you accept donations using Github and Liberapay so those work fine for me as alternatives.