https://esahubble.org/images/opo0328a/

Hubble mosaic of the majestic Sombrero Galaxy

Cyberpunk aesthetic:
https://images.hdqwalls.com/download/cyberpunk-city-rt-2560x1440.jpg

The "cosmic cliffs", from the James Webb telescope.

The seemingly three-dimensional “Cosmic Cliffs” showcases Webb’s capabilities to peer through obscuring dust and shed new light on how stars form.

So-called mountains — some towering about 7 light-years high — are speckled with glittering, young stars imaged in infrared light. A cavernous area has been carved from the nebula by the intense ultraviolet radiation and stellar winds from extremely massive, hot, young stars located above the area shown in this image.

Press release and link to download the (14,575 X 8441) image here.

Star size comparison, with the Sun as 1 pixel

Full resolution version:
https://farm5.static.flickr.com/4138/4820647230_faba1c9f3b_o.jpg

One more :)

https://www.reddit.com/r/wallpaper/comments/1164moq/futuristic_paradise_7680x4320_8k/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button

https://www.reddit.com/r/wallpaper/comments/10m6p6c/observation_deck_7680x4320_8k/#lightbox

https://www.reddit.com/r/Astronomy/comments/80uh4v/i_turned_the_pluto_image_into_an_8k_wallpaper_for/#lightbox

A pretty Pluto

https://wall.alphacoders.com/big.php?i=1345265

might require some cropping to get the right dimensions, but to keep it simple, could take one of the giant pics of the observable universe (e.g. here, or the 25k x 25k hubble pic on google drive here). it can be nice to feel very very small!

Space w/ some human structures

is acceptable as well.

https://wallpapercave.com/w/wp12000433