Download GCAM 8.8 for your Samsung Galaxy device Exynos and Snapdragon variants : r/GalaxyS21
With GCam astrophotography enabled on S21 Ultra. 10 min long shot worth it after all :) : r/s21ultraphotography
GCam for S21 Ultra? (ISO) : r/GalaxyS21
Galaxy S20 Google Camera Exynos | Better Pictures! - YouTube
Amazon.com: SAMSUNG Galaxy S21 Ultra 5G Factory Unlocked Android Cell Phone 128GB US Version Smartphone Pro-Grade Camera 8K Video 108MP High Res, Phantom Silver
GCam for the Samsung Galaxy S21 : r/GalaxyS21
Snapdragon S21 Ultra Stock vs Gcam Telephoto Comparison : r/samsung