> The old school internet was completely destroyed when all wysiwyg tools where killed for no reason about 15 years ago.

The power of CSS has increased to the point that you don't really need Javascript for layout any more.[1] So WYSIWYG tools could work again. Probably faster.

[1] https://codingstella.com/15-advanced-web-development-techniq...

That suggests a new kind of WYSIWYG editor. It only does declarative HTML/CSS, no Javascript. Maybe it edits the DOM, not the source. When you save to a file, the HTML and CSS are generated. Maybe use Webkit to do the rendering.

If you want any Javascript, it has to be in a separate .js file, not mixed in with the document.