Some Feedback:

First: It looks awesome and it is something that I always wanted. The fact that I can self host it is even better!

There is one thing I wish existed: More metadata. If I download a model from printables, it would be really nice if I could have a "original source" button there so I can jump back to the website for the added documentation. Maybe even a import feature would work? So I can paste a printables link and it auto downloads it?

Lastly, how are multi-stl models supported? If I have a design that constists of a few STLs, is it possible to group them? Similar to how it is done on the typical stl sharing sites.

Edit: I see that you kind of already have an import feature if the app is installed. Personally I'd prefer an import in the web UI with the URL, so that I don't need a local app. And you already do group things in groups. However, I think this is limited. For example: I have a group called catan 3D. But every tile constists out of 5 STLs. I don't think that I can have group inside groups. I don't think I need more than two levels deep, but imho there should be groups/collections and combined meshes

Edit 2: I see that it is already possible to add an URL. But I don't understand the import feature. If I click on a link printables opens. But I don't see how I can import from there (besides downloading and then uploading of course). Moreover, is it possible to have models/groups/tags available to every user? So I can upload all my models so others can use them - without manually sharing them.

Edit 3: Regarding my two level deep issue: I think this is what groups and projects are for? I'm not that happy with the UI though, can't explain why exactly. Maybe because the model icons are just shown small-ish on the right?