Let's try to understand why SPAs are already standards of today's web. Instead of building a UI in the traditional way (that is, requesting rendered web pages), SPA designs allow developers to write code in a totally different way. There are many Model-View-Controller (MVC) frameworks, including Angular, React, Vue.js, and so on, for developing web UIs rapidly, but the essence of each of them is pretty simple. All MVC frameworks help us to implement one design pattern. That design pattern is no requesting of web pages, only REST API usage.
Modern frontend web development has advanced a lot in the last decade (2010-2020). In order to exploit the features of the MVC architecture, we have to consider the frontend as a separate entity that talks to the backend only using the REST API (preferably using JSON data).