in case of SEO, almost all single page application (SPA) have poor SEO. it's because these kind of website pages are not fully rendered by search engine indexing bots and things like meta tags and meta descriptions and page content are not available for these bots. so you have two solutions:

1- convert all your webpages to static HTML file. this way your pages are fully static and fully loaded so bots can detect everything. but as the name suggest, static pages may not be very useful since you know, they are static.

2- use SSR (server side rendering), for this you need to use something like NUXT. but the thing is, you need to deploy your nuxt application on a nodejs enviroment. so many shared hostings won't do the job. in general, SSO is a good solution if you really care about the SEO, but you need that node js server to render your code and return the result to clients (like bots and users)