Same for the other languages - they likely won't have the performance of C++ or Rust. But I'll test them anyway, even just for the academic exercise the endeavour is worthwhile. Thank you.
That said, given your original request, I don't think it has much to do with language choice. Displaying a very large number of rows in a data grid or similar is a classic GUI task in line-of-business apps, and the answer has always been either virtualization (lazy loading) or pagination.
One trick to improve UX when virtualizing data is to do preloading asynchronously in the background - ideally on a separate thread - and start it before the user scrolls all the way to the end (e.g. when there's still a couple of pages of data left).
One thing that I would like to discover is how to adjust the scroll bar size so that it appears as if more records are loaded than actually are.
I think it's been out of date for a long time with modern computers having much more RAM and speedy SSDs (and also JVM optimizations). For actual run time performance once its loaded the JVM has had great performance in the early 00s already and improved since. And for server side it was never an issue as you don't restart the server very often (so the JVM is always already loaded).