Correct way to virtualize a list with nested dynamic items?

[gabrieljim]

This is my use case:

Outer list:

• Item 1
• Item 2
• Item 3

On click, these items will fetch specific information for the clicked one, and this response can contain thousands of items, so we could end up with

• Item 1
  • InnerItem 1
  • InnerItem 2
  • InnerItem 3
  • InnerItem 4
  • InnerItem 5
• Item 2
• Item 3

Only one will be open at a time
Soooo, obviously I can't really load 5k items at once since the browser will hang, and I was thinking how to correctly use virtuoso for this use case.
Also, it is crucial to avoid having a nested scroll since the outer list is already scrollable, and virtuoso should recalculate based on this scroll

From gathering info, customScrollParent and GroupedVirtuoso seem to be the two solutions for this. Which one would you recommend? Which one is most performant

Thanks a lot for any input!!!