Accessing NISAR DEM

Hello, I'm trying to run ISCE3 example workflows but the nisar-dem bucket needs credentials:
https://github.com/isce-framework/isce3/blob/5e36b8a1b90d093128e84d46b2b63b3adf646981/python/packages/nisar/workflows/stage_dem.py#L16

The nisar-dem is also used for OPERA processing (cross-ref https://github.com/opera-adt/COMPASS/issues/216#issuecomment-1915216236)

As a workaround I'm assuming NISAR DEM is effectively identical to the publicly accessible Copernicus DEM (https://portal.opentopography.org/datasetMetadata?otCollectionID=OT.032021.4326.1) converted to ellipsoid heights (EPSG:9055+3855). The NISAR sample data https://nisar.jpl.nasa.gov/data/sample-data/ does include a small dem tile but unfortunately the CRS is listed as EPSG:4326 rather than a more specific 3D CRS.

To avoid potential discrepancies it would be great to just access nisar-dem, and it seems the intention is to make it public?
(https://github.com/isce-framework/isce3/issues/5#issuecomment-884536230)

Start with the linked line in python/packages/nisar/workflows/stage_dem.py and trace how the workflow accesses the nisar-dem bucket. Review the referenced NISAR sample-data page and linked issue discussions to determine the intended public-access path; done means the workflow has a documented, supported way to access the required DEM without private credentials.