I want each user to have their own private namespace either on registration, or first login, or whenever they decide to implement it. I can work with any of those approaches. The wiki is intended to become a place for discussion of alternative spiritual/religious beliefs. Earlier efforts have failed to provide adequate protection from radical evangelical persons and other kooks. The wiki needs a common area open to the public, and private "chat rooms" that I think can be managed adequately by ACLs on namespaces, but most critically it needs private namespaces where a person might keep a personal journal safe from prying eyes. There are post-Catholic, post-Scientology, and post-Amish persons who really need their privacy, but also desparately need a community. When one's spiritual growth puts one at odds with family, coworkers, etc, there are problems. I don't see the wiki as the only lifeline for these persons, but a useful thing it could provide is access to Zoom meetings, notices about face-to-face activities, etc.
My latest effort has been with Adrian Lang's userpagecreate plugin which looks like it can do what is needed, but so far I have not been able to get it to work. Perhaps I'm not installing its template properly.
My technical background is in website development, mostly of online policy and procedure manuals in a hospital setting on a closed intranet. However that was some 20 years ago and I have not kept up with the technology.