I guess to get a feel for the system side (CDN, emails, etc) an online staging install would be best.
I have two localhost installs. One is a development install and the other is a production install. These let me experiment and experience the forum in all kinds of ways. As an Admin, a Moderator, a TL0 New member, a Silenced member, a non-English member etc. etc.
I don’t know if a comprehensive documentation covering all the nuances of various combinations of settings is even possible, but at best it would be a massive undertaking. IMHO nothing beats hands on experience, and searching / asking here when necessary. If you have a question there’s a good chance it has been asked here before, and if not, there’s a good chance it will be asked here later.
I think looking at the various Admin pages will for the most part be self explanatory, i.e. things are named well and are descriptive of what they represent.
If you can read code fairly well, the Core files can be a big help