How to include all the Symbols used in my content to render my content on the server side (SSR)?

By default builder lazy loads the symbols used in the content. If you want to render the page all at once and want to opt out from lazy loading symbols, pass noTraverse=false in your api call

If you’re using the rest API directly just append noTraverse=false to the query string, and if you’re using the sdk:

const page = builder.get('page', {
  options: {
    noTraverse: false
  }
 // userAttributes: {.....}
})

resource: Content API docs