Are there any negative impacts from prefetching too many elements? If so, what are they?

you want to try to be conservative with the prefetching because

  • beyond a certain amount it may slow down the processing of the page if it’s a CPU heavy page.
  • It may also start to empty out older content and replace it with newer stuff if the application cache is small (probably not going to be an issue).
  • Lastly if you’re trying to prefetch too many docs, shopify may start to limit you thinking you’re trying at a DDOS attack. Note that this can only potentially impact the prefetching and XDN caching and your users will still be able to browse the site albeit without the prefetching. To avoid this, the XDN prefetches only documents that it already has in the cache

In short, it depends but isn’t best practice to load more than what’s accessible from within the viewport

Please check description above