The closest thing it shows to Xbox Series X is Xbox 360. So can you submit a run on Xbox Series X, and if so, how?

Just sumbit the run and marked the run under the Xbox 360 platform and in the description on the run you can simply say "Played on Xbox Series S/X" and mods would be add that version to the list of platforms and also you need video proof to the run but you can record your screen with your phone if you dont have a capture card