How are you going about this? Asking because I thought about doing something similar (e.g., Makerspaces, hackerspaces, Fab Labs).

Luckily a few others here in Idaho have done it by way of a Friends of the Library official non-profit 501(c)(3), so I have a model to follow that works in our region and for our rural conservative conditions. The standard non-profit benefits apply: we apply for a lot of grants, we set up endowments, accept land or stock as gifts, take on capital projects like building a library. The public library can then lease from us (probably for $0) or if we put a large enough endowment fund together we would very much consider taking it all private vs just a purpose built building for the library.