Rendering of large dataset in pvbatch script on computational node

Good afternoon,
so I have an automatisation pvbatch script for opening a large dataset of .pfb type slicing the 3D to 2D adjusting view and than taking a screenshot. This worked now well for with netcdf before and also for .pfb (with the corresponding plugin) and a small dataset. (MB)
But for a very large dataset(GB) eventhough running interactivly with xpra on a supercomputer node, I only get the gray background in the screenshot.

Any ideas would be very appreciated, if it helps I can also share more code.
(I just use the PFBreader with ns.global option, the sliceing and adjusting view with renderView (which works fine as i want for small datasets and I also do .UpdatePipeline and Hide() for the original data and show for the slice and at the end i do renderView.ResetCamera() and Render() and `ImageResolution=renderView1.ViewSize.
As I said it works fine for small datasets I just get the gray background for very large datasets how can I adapt my program or is it even possible?

To run the script at the end I run the program while being on the node interactivly with:
OMP_NUM_THREADS=48 srun -c 48 “$PARAVIEW_PATH”/bin/pvbatch “$PARAVIEW_SCRIPT” “$NETCDF_FILE” --use-offscreen-rendering

I have the amount of points in slice:757291520
And the needed memory size:61771520 bytes
So it is really large compared to the smaller one.
Maybe is there a way to reduce the grid points amount (average 10 nearest points in paraview with the filters?).

Any ideas would be very appreciated!