Hello rkwik,
Quality parameter in the Batch process dialog is only considered, if you are using Depth Maps as a source data for the Build DEM operation. For other source options (like Point Cloud), the quality parameter value will be ignored.
The most common approaches for the DEM generation assume the following steps in Python:
1. Build Depth Maps (using desired downscale value) -> Build Point Cloud -> Classify Points (optionally) -> Build DEM using point cloud as a source.
2. Build Depth Maps (using desired downscale value) -> Build DEM using depth maps as a source.
Filtering parameter is also considered only for the depth maps generation.