Read the guide & seems cool, reacted to setting "Above Normal" priorities as that can make WinUAE extremely unresponsive on even pretty fast CPUs (especially single core, I'd assume). If sound is struggling you should even set it to Below normal. Even if the goal is to make it like only WinUAE is running, that's not the case
That guide works fine if you never want/need to use Windows, such as for file transfer from PC/Internet or play mp3 or check email or such. (The start menu, taskbar, systray will be inaccessible.) But ofc if it's on a USB stick or LiveCD you can reboot if you want Windows again.
I went a different route, my goal was to cold-start a laptop, see black, gray, white, WinUAE starts Workbench (and if you exit WinUAE, to be a fully functional Windows machine). I'm waiting for an SSD to make the timing of this 'emulated Amiga bootsequence' be more realistic - right now the black part of the bootcycle (Windows loading) takes over a minute, and that's not really what booting an Amiga looks like
To get around some of the hard-coded 'features' of XP takes a little more strange tweaks.
When I get the SSD I'll film it (you know, "Youtube or it didn't happen"... kind of) and write a guide.