SPA or single-page application is the most commonly used pattern for modern web applications. The main function of SPA is to build a single web application that is then delivered to the user. It rewrites the content of the page with regards to each data change or user interactions. Mostly SPA has a router that helps deep linking as well as page navigation that can consist of multiple components.
Even though SPAs are quite modern, they are far from perfect as it has a lot of setbacks.
Shortly, it lacks the framework complexity and due to the loss of search engine optimization, the app is not being presented until the user sees it in the browser (which leads to losing many keywords that will stand in the way of your attempts of going up the search ranks). The other con is the browser performance that prevents you from delivering a smooth user experience.
It all adds up to the main issue that is a scale, and the solution to which is Micro-frontends!