https://www.youtube.com/watch?v=n7uehyY8tpY
The resolution on Xbox Series X seems to be higher than PS5 when pixel counts are performed during the same scene on each console. Some example pixel counts for PS5 and Xbox Series X during the same scenes are below. Note that these figures are approximate.

Xbox Series X: 3733x2100 and PS5 3584x2016.
Xbox Series X: 3648x2052 and PS5 3456x1944.
Xbox Series X: 3342x1880 and PS5 3093x1740.