This was actually possible to do all the way up to and including Win7, which even had the icon taskbar working in that "Windows Classic" theme. And it was very good design - pretty easy on the eyes and not distracting, but you could also tell which element is which easily at a glance (unlike these days, when everything is flat).
However, the nice thing about the Windows Classic theme is that you could change all of the colors arbitrarily, including the bezels.
It's so sad to look back and remember how insanely customizable desktop UI was back then, compared to what we have now. In Win11, you can't even have a vertical taskbar anymore.
Likewise if you wanted the non XP (Luna I think it was called?) styles you could just stop the theme service and it was effectively win2k style.
Literally the exact same kernel if you count XP x64 Edition. Even the exact same Windows Updates apply to both. :)
But yeah, Windows XP (32-bit; NT 5.1) and Server 2003 (NT 5.2) were pretty close. The latter was pretty much "XP Server Edition", albeit some significant kernel changes were made, especially to improve network performance.
It was the only time that the client and server versions of NT had diverged. Granted, the Windows Server team didn't feel like NT 6.0 was ready for the primetime when Vista launched, but instead of having two branches of the operating system again, Windows Server 2008 was launched identifying as "Service Pack 1" from the get-go, with Windows Vista's SP1 updating the OS to include all of the underlying improvements made for Server 2008. From that point forward, they were the same, including the same Windows Updates. It's also the point that Windows Vista got all of its technical flaws fixed. (Reputation flaws not withstanding, it wouldn't be until Windows Vista SP3 aka Windows 7, that the reputation would get reset...)
Driver compatibility was terrible, as you might expect, but it could support a vast amount of memory (relative to XP). I used the base O/S only to run VMware Workstation, and then ran small instances of XP, each dedicated to a task like audio, video, etc, on top of that. Along with FreeBSD and various flavors of Linux.
That was my daily driver until late 2010. Solid as a rock.
But having that UI show up in 640 VGA because it couldn’t find drivers would make you angry, and you’d take it out on it.