If you are missing lazily loaded images, try increasing setViewportHeight to a larger value, e.g. 16000.
If you are missing some resources, create a debug log using setDebugLog and parse it. The debug log shows a lot of detailed information about the conversion. It is useful for identifying parts to speed up performance.
// some content is generated by your JS ... // everything is ready let trigger = document.createElement('div'); trigger.setAttribute('id', 'conversion-trigger'); document.body.append(trigger);
and your API code