You might have already looked into this, but a lot of public libraries are part of larger interlibrary system that will include other public libraries + college

You might have already looked into this, but a lot of public libraries are part of larger interlibrary system that will include other public libraries + college libraries. Where I'm at the consortium includes most of Colorado and Wyoming, with a total of ~30M volumes. I can request them online and they're typically available at my local library in a few days.