[fraXis]

I would recommend WindowBlinds to achieve the "grey, boxy UI" look. As for a Windows 2000 theme out of the box, I am not sure, but I know it can make your Windows 10/11 UI look and behave like Windows XP.

There is a custom skin editor as well, so you can tailor the look of Windows to anything you choose, so you can probably get very close to the Windows 2000 look you are seeking.

https://www.stardock.com/products/windowblinds/

[delta_p_delta_x]

Cheers. Some of the themes look pretty good! I used to use StarDock Start and StartIsBack back when I was using Windows 8 to, well, get the Windows 7 Aero theme and the start menu back.

That being said I do notice that many of the rounded corners aren't fully transparent...