Well, it's not for MacOS, but software to run animated wallpapers exist for Windows.

One example is the very popular WallpaperEngine [0]. Another cool one (and open source) is Lively Wallpaper [1].

Selfless plug: I've also developed and released LumoTray [2] which is a wallpaper/screensaver manager for windows with some other extra features but without any animated wallpapers except slideshows as I still find it a bit of a resource waste for something that I rarely see.

[0] https://www.wallpaperengine.io

[1] https://www.rocksdanister.com/lively/

[2] https://lumotray.com/