PS5 UI is 4k. XSX is 1080p. There's nothing you can do to change that. Can't remember why Xbox did that but it had something to do with saving RAM space. (EDIT. Xbox released a 4k version. Not sure if it's native 4k or upscale or reconstructed though.. hence the difference you see)

Also when the games first released, the consoles were tested on several games. PS5 outperformed XSX on several games, while rarely loosing out. Digital foundry, VG tech and Another channel tested them. I remember seeing the first 5 games tested, 3 of which were new gen, the last 2 were previous gen. PS5 beat the XSX in graphics fidelity sometimes. But mostly on framerate.

It got so bad that the AC Valhalla had way higher res pixel count on PS5, and higher fps too...that Xbox complained at which there was a patch released which made the PS5 graphics and fps WORSE. BUT it still outperformed the XSX. PS5 fans were outraged at PS5 getting a "patch" when it didn't need one, which only detuned the performance.

So generally speaking, graphics are usually the same or close enough. They're usually fixed but some games have adaptive reconstructed resolution techniques which means the resolution can reach 4k, but can dip below when it's demanding. On those games PS5 had higher resolution. But when it's fixed. Its the same obviously. But then the PS5 most certainly offers better fps, especially on 120fps mode where there's huge gap.

Aside from this mode, there's not always necessarily huge differences. It's still neck and neck pretty much