This is good advice. Learn about markdown syntax, try Obsidian to write notes that can be interrelated in a network, add drawings, and export selected notes to HTML. You can further stylize all of them with some custom CSS. There are many “content management system” (CMS) like Obsidian does. I’d self host ghostwriter. But just search for a CMS on awesome self hosted list and find something popular that’s akin to you for whatever features or underlying tech (e.g. Wagtail for django web devs)