Our first recommendation would be to use the Xbox mobile app. We've tested this method out here at the PX office, and have managed to successfully get the game installing on Xbox Series X. Simply open up the mobile app, search for Hollow Knight: Silksong, and install it to your device of choice (you'll have to link a device if you haven't already).

Yes, Hollow Knight: Silksong is available to play through Xbox Game Pass! Specifically, anyone using either Xbox Game Pass Ultimate or PC Game Pass can play Team Cherry's long-awaited Metroidvania sequel on Xbox or PC or on PC, respectively. You cannot play it on the console specific Xbox Game Pass Standard tier, however.

Multiple social media users and data from services like DownDetector are noting that the service is down for many people, with a massive spike in reports pretty much the moment Silksong became available.