If you weren't aware previously, you'll be pleased to learn that you can still program in Flash if you really want to, and distribute your programs on the web. https://ruffle.rs
We have the web, we don't need ruffle, what we need is indeed a open source flash editor. Wick editor was quite close, by outputting standalone html files
stuaxo|24 days ago
lukan|24 days ago
https://www.wickeditor.com/
Of course, not at all on the same level like flash was, but some parts worked really nice.
Unfortunately it is abandoned. (I thought about taking it up, but would require lots of effort, basically rewriting core parts)