@devloic have you heard about Hypothes.is open source web annotation tool?
It's sounds like really close to what you were trying to achieve and integrating it with Joplin Webclipper really seems like not a big deal comparing to original ambition to write annotated web from scratch.
This tool is huge and revolutionary - could be a killer feature to integrate it's browser extension with Joplin Webclipper to also save your selected text annotation with your own comment into Joplin for future reference.
Not only that - you'll also receive emails about folks reflecting on your comment ultimately making your outdated/not relevant notes improve by collective mind correcting you about some piece of knowledge.
If only Hyphotes.is could evolve into something like community notes on X - which I think it eventually will - that's just going to be perfect.
Gosh, If I only had all the time in world...
P.S. wait, have I found Joplin plugin exactly like I've described? YES!!!
Here's plugin's topic: