And once again, Microsoft fails to deliver on its promises with KB5083631... Xbox Mode is completely different from FSE (Full Screen Experience, or Windows or Xbox Full Screen Experience).
I tested FSE for months on my laptop. At the time, I enabled the feature through a program. FSE worked beautifully! You chose an application to be the "dashboard," in this case the Xbox App, there was a list of programs to choose whether or not to start with FSE on Windows login, and you restarted the system and it would start with the Xbox app in full screen, optimizing background services and prioritizing games, increasing performance.
Now, they've released "Xbox Mode" which does NOTHING that FSE did and is nothing more than an interface to be controlled by the controller and nothing else, they even removed the option to start Windows already in Xbox Mode.
This is a huge rip-off for those who were expecting Xbox Mode and had tested FSE.