Private Vimeo vids on my domain under login?

Hi,

I may find myself in the need of distributing some of my videos through Vimeo (a friend has a Business account and will kindly lend me some space).

I know that privacy settings allow vids to be played only from a specified domain (good), hence I'd like to embed them in one of my websites. Although I'd really need user authentication this time, i.e. to grant access to entitled users via some sort of login.

What would be the easiest/cheapest way (free, or borderline-free would be best), if there's any, given that my current 3 websites are all SSG based ones (Jekyll on GitHub Pages, Gatsby on Netlify, plus a plain static one).
A friend suggested a custom Wordpress installation, but I've quit WP a long time ago and never regretted a single day without it.

Thanks!!