How to save a custom made website as a template

Let's suppose I created a site made entirely with GP Premium and GB blocks. I have different types of elements, pages and posts with different layouts, I chose fonts and I added custom CSS. Just like the ones in the Generatepress library.

Is there an option to save it as a template and reuse it whenever I need it?

The idea is I don't want to save and import it "in pieces" using first the export/import module settings like the ones described in the documentation (https://docs.generatepress.com/article/import-export-overview/), then the content, using WordPress import/export options in the Dashboard, and then adding my own CSS. I would like to have it as a "whole" and upload it directly from my computer, exactly as if I were choosing and installing a site starter from the "Site Library".

Is such a thing possible? Definitely yes, but how?

Thank you for your support.

Best regards,
Marcel