If I have a high end pc, is there any reason to look into a series x?
I've got both. It depends.
XSX is way, way more convenient than a PC. It just works. It's ridiculously fast and reliable. And Game Pass is fully integrated in to the entire experience, so you can quickly browse, discover, install and play games all from the comfort of your couch and controller with such a frictionless experience. And there's no messing with multiple launchers, every game has Achievements and links to your same friends list etc.
But then there's PC, and if you have a RTX 3080 for example, there's no getting around the fact that it's more powerful than the XSX by an order of magnitude. You can enjoy native 4k on anything you like, or 120fps on anything you like, and throw in some ultra settings etc. You're in control. You can also mod games. And of course the PC games library is way larger and you'll have access to Switch/PS5 exclusives from Silksong to Project Athia.
All depends what's important to you. But if you just want to play the games with no messing around then that's always the beauty of consoles.
I love the convenience of console personally, but I also love the power of PC. And whenever I'm playing a game on console I can't help but think it'd look way better on the RTX 3080 lol.