If you want something boring, use a static site generator like Hugo. But you already said you found them restrictive
I built my previous site with Ruby Mustache, an extremely simple templating thing. But I abandoned it because it got hard to maintain.
My current site is plain HTML and CSS. This is the way if you want ultimate customizability. It works pretty good and I would recommend it. Simpler is better.
Remember: Having a website was one of the ways people communicated on the net back in the day. HTML and CSS are intended to be used by regular people, they are very easy to learn. Don't be scared of them
There is no decent WYSIWYG html editor i know of