SEO Best practices for large amounts of external data

Code stack you are integrating Builder with
e.g. NextJS, react, Shopify
Angular with an external REST API

Last year we inherited a site that was partially complete, with many core technical choices already set in stone. One of those choices was around population of SEO data: meta description, title, h1 tags.

The site in question makes calls to the product API, in the browser, for all product data, as well as for all of the SEO data. This helps with site speed, but, as it turned out, Google was not interested/able to render the js pages, and the organic SEO ranking tanked. We were advised by SEO experts that it’s not best practice to expect Google to execute front end code for SEO purposes. Currently there is a pretty awkward and kludgy solution in place. (Prerender was not able to render the Builder pages out of the box either.)

Is it best practice to render SEO data in Builder, before the content is sent to the browser? And, if so, how does interacting with a third party API in Builder affect site performance? Does the Builder CDN implementation reduce the impact of SSR?