My thoughts…
I’d recommend looking at @RiderExMachina’s bestdistrofor.me project, he makes it really easy to commit to and everyone knows what’s needed incrementally so whomever has time can just jump in and no one’s afraid of potentially large or nebulous commitments.
If you break it down into parts and where necessary those parts into more parts you will get help and the more evidence that the project will probably succeed whether anyone likes it or not the more of that help will come.