Hi, is it possible to use Origins on a server-side-only way?

The reason for that would be to be able to have some type of compatibility with geyser, only if bare minimum.

Currently, no, and doing so may require restructuring the codebase and applying work-arounds since it wasn't really designed to be only used on the server-side. There is a plugin that you could use, OriginsPaper, which is built from the ground up to work only server-side, but do note that it's not officially supported, so any issues you come across using it should be reported to its own issue tracker.