I have doubts regarding the HTML documentation in Metronic, Can We use all libraries and all other components in HTML documentation in angular?
The HTML documentation is applicable for the HTML version only since it uses jquery and other angular incompatible plugins.
The Angular version comes with its own documentation that you can find here.
Please note that the global CSS of static components is all available in the angular version, except those jquery plugins. So most of the templates are reusable in the Angular version by copy-pasting the HTML markup from the HTML version.
However, if the Angular version is too limited for you, you may request a refund using this form.