A DESI DR1 Search for Directional Gradients in Galaxy Population and High-Redshift Quasar Observables

Preprint. This work reports a reproducible null-result search for large-scale directional gradients in public DESI DR1 data. The analysis tests LSS density, FastSpecFit galaxy-population residuals, and high-redshift QSO line observables under corrections for survey geometry, redshift trends, nuisance variables, and spatial block-null tests. No robust repeated directional axis is detected in the tested DR1 tracer/property families. The accompanying software and reproducibility package is archived separately as Zenodo DOI 10.5281/zenodo.20433884.