Adding folder with "mini-site"

Hi all,

I'm trying to create a Squarespace homepage for my teaching and I already have some courses I wrote in self-contained jupyterbooks. If I understand correctly, starting with 7.1 and the demise of the developer mode, there is no way to upload a folder to Squarespace, so the only way I see it possible to use my Jupyter Books as course pages is to have the courses hosted somewhere else (e.g. GitHub Pages) and just put links in my Squarespace page.

Is this correct or there is another way I don't know?

It would be extremely tedious to rewrite all my content in Squarespace pages, not to mention that since we're talking about mathematics and computer science materials, there are extra difficulties with formulas etc. So I would really want to keep the courses as I have them, but link them in a more self-contained, professional way to my Squarespace site.

Thanks!