8 – How to create dynamic webforms / entities in the decoupled concept Drupal + Vue.js?

I want to create a web application for a client using the decoupling concept (Drupal 8, Vue.js).

One of the client demands is to have the possibility to create dynamic webforms with specific fields and relate them to a content type (e.g: Article).

He creates the webform “A” and relates to Article 1 and Article 2.
He can also create another webform “B” for Article 3.

With Vue.js and REST API I don’t found any documents or articles about this concept. The same for the creation of custom entities using REST API.

I ask for resources (books, videos, projects …) or an idea on how to do that.

Thank you in advance.