The table loads super and editing is also slow to start when rowexpansion is added for large data 2000 rows by 64 columns and 10000 rows by 5 columns. It looks like lazy load is not implemented on it. I was thinking of just loading expanded rows only when the button is clicked. I tried to bind with *ngIf and the expand button click but it didn't expand. Even conditionally disabling using *ngIf for tables with no related record didn't work. Is there any way of making it lazy load?
I have live example in stackblitz.
It seems like this is a bug on primeng but I found a good workaround. Mainly, the solution involves removal of rowexpansion completely and replacing it by <tr> that will contain a div or another component that appears conditionally when the Expand button is clicked.
See the updated stackbitiz with no lag.