To get the best clarity for a 6K setup, you should look for "Original" or "Full Size" downloads from these high-fidelity repositories:
: Despite the name, they host "5K" and "8K" categories that often include cosmic cliffs and nebulae captured by the James Webb Space Telescope. 6016x3385 Galaxy Wallpaper">
: The most reliable source for true-to-life deep space imagery. You can download massive TIFF or high-res JPEG files from the ESA/Hubble Wallpaper Archive or the NASA Science Multimedia page. To get the best clarity for a 6K