And even within the Control Panel (the older one), there's multiple visually distinct UIs:
1. First, there's "Windows 7 style" applets like "File History", "Power Options", and "Programs and Features". I'm not sure how to summarize these beyond that they have a resizable window and usually have some options in a sidebar on the left, but they all have a visually consistent look (which was a lot more obvious before Windows 10).
2. Next, some Windows 7 era applets use a different interface which displays in a (mock) file browser, like "Devices and Printers" or "Fonts".
3. Then there's some older applets which use a Windows XP-era interface in a small, fixed-size window with tabs at the top, like "Date and Time" or "Mouse".
4. Finally, there are a few applets which have a completely unique interface, like "Indexing Options" or "Device Manager".
5. Oh, and I forgot to mention: some of the applets in the Control Panel open up a Settings applet when clicked, like "System" and "Taskbar". But even this isn't consistent; some applets in Settings, like "Mouse" have a "additional settings" link on the right which opens the Control Panel applet when clicked.
Confused yet? Don't worry, the next version of Windows will assuredly find a way to make it worse.