@cnsyoung People have been talking about #Quarto, recently.
https://quartopub.com/

Also a lot of work around @LibreTexts.
There are some benefits to collaborative work on #PubPub. https://www.pubpub.org/

Sounds like #ManifoldPub finds favour with presses. https://manifoldapp.org/

Of course, having your own instance of #Pressbooks can be very neat. https://pressbooks.org/

There are other options and considerations.
What are your requirements?