Why doesn't live wallpaper actually animate?

I see no animation on lock screen or home screen (or any screen for that matter) when live wallpaper is set.

In the settings Settings > Wallpaper> Choose a new wallpaper > Live the preview works fine but if a live wallpaper is set to both it doesn't animate. The same issue was happening on my old phone under iOS 11 and 12 so I thought it was something specific to the phone but after upgrading this issue still remains.