I have no idea of whether it is appropriate to praise Miraheze or add more information (I am more of a Wikiversity/Wikipedia editor). But as far as I know, Miraheze permits private wikis that most closely resemble a MediaWiki project. I discovered Miraheze while contemplating a proposal requesting that Wikimedia make a private wiki for educational purposes. Students compete for grades, and the open structure of Wikiversity allows students undesirable access to each other's work in progress.
I have a "wikinode" at https://wright.miraheze.org/wiki/Main_Page that permits me to "peek" into the private work of 100 students, and Miraheze charged me '''nothing'''.
For more information about my participation in Miraheze, search for "Guy Vandegrift in https://meta.miraheze.org/wiki/Miraheze-2-year
For my effort to use wikipedia:OpenStax textbooks, see wikiversity:OpenStax College/Astronomy --~~~~