You can change the system font to Lucida Grande with macOSLucidaGrande, you can customize the folder icons with ClassicFolders, you can customize the icons with LiteIcon and the icon set from this GitHub repo, you can customize the dock with cDock (paid but only costs $10 USD and has a free trial), and you can download the Mac OS X Tiger wallpaper from here. The window titlebars buttons are a little bit more... Source: over 1 year ago

And to change the icons, download LiteIcon: https://freemacsoft.net/liteicon/. Source: about 2 years ago

It was possible until macOS Big Sur come out. http://freemacsoft.net/liteicon/. Source: almost 3 years ago

I much prefer the GUI of 10.15, but I like the Big Sur icons specifically, especially all the fan-made ones for third party apps. So I used LiteIcon and changed all my app icons, even though I’m still on Catalina for software support reasons (and partially for the GUI lol). Source: almost 3 years ago

There is a tini and handi apps for that icon change, and thousands of icon on web Icon change software. Source: about 3 years ago

BGinfo is one very simple approach to your basic premise. Source: about 1 year ago

Check out BGInfo. https://learn.microsoft.com/en-us/sysinternals/downloads/bginfo. Source: over 1 year ago

BGinfo runs on boot to overlay useful information on the wallpaper. Source: over 1 year ago

Microsoft has BGinfo @ https://learn.microsoft.com/en-us/sysinternals/downloads/bginfo that is free and can be pushed to machines to display relevant data like machine name and IP right on the desktop and its highly visible to end users. Source: over 1 year ago

But, I recommend taking a look at bginfo. A lot of places just use this to constantly display the system's info on the Desktop. It seems like a campy solution, but it's a popular campy solution that no one questions. Source: over 1 year ago