Once you're on Windows 11 25H2, opening Settings > Gaming might show a new, fourth option saying Full screen experience.
The new Xbox full-screen experience doesn’t load the full Windows desktop or a bunch of background processes, freeing up more ...
TL;DR: Microsoft's new Xbox Fullscreen Experience app, designed for handheld Windows 11 25H2 gaming PCs, optimizes system resources by disabling non-gaming functions, freeing up about 1GB of RAM.