A popular insider is arguing that Sony won't allow PC ports on future Xbox consoles. Many gamers disagree since any Windows-based system should support Steam. Microsoft may soon release an Xbox handheld that could act as a test case for booting PlayStation's cross-platform games.
Honestly, I don’t think it would be all that difficult. From my understanding, under the hood the Xbox Series X/S are basically just a normal x86 PC. They even say the OS is ‘Windows 10 Core’, and some stuff is already fully cross-platform.