Hi there!
In your doc, you mention that VanillaJS project is not recommended and JS frameworks use is strongly recommended. I'd like to challenge this statement as StencilJS.com (a web component compiler) makes it possible to build a production app in vanilla JS (standards-compliant web component, Stencil - A Compiler for Web Components - Stencil). Stenciljs is the compiler developed to build the ionic framework (UI web components) among others.