Thanks for an amazing introductory to web components! I fully agree with you regarding Web Components complementing frameworks such as Vue or React. They work together very nicely especially if you are building a framework-agnostic design system that works across multiple technologies.
I recently wrote about creating thin wrappers to make web components work with React if it interests you. https://muhimasri.medium.com/web-components-with-react-hooks-f0e2a62de323