If you want to pay for audiobooks, Libro.FM is a DRM free alternative that allows you to easily download your books without any issues that Libation solves for. It also supports local bookstores in your community while not giving more to Amazon. Only a handful of books aren’t available on Libro but it’s been a seamless transition for us. It’s only going to be difficult if you’re one of those folks who returns/refunds audible credits regularly as it’s not easy to do with Libro.

Not sure if this van_dam might work for you. I found it randomly searching through my Unraid server’s App store and it seems to be built around 3D printing files. As a note, I haven’t worked with this one personally yet since I haven’t had the time to get Postgres and Redis set up, but I have this pinned to come back to it. Could be worth a look!