The solution of black screen on some files at Wallpaper Engine:
This video is HEVC/ HVC1 (H.265) encoded,
so the size is even smaller than the original video with same quality and resolution.

However, Wallpaper Engine does not native support HEVC format.
Only HEVC codec windows extension or LAVFilter can solve this problem.
https://help.wallpaperengine.io/en/videos/lav.html

If your computer have a GPU which native supports HEVC codec,
this is recommended that installing LAVFilter.
https://github.com/Nevcairiel/LAVFilters/releases

**Caution**Only install this will make your CPU to do all decode process, not GPU.
Install the HVC1 codec on the microsoft store.
ms-windows-store://pdp/?ProductId=9n4wgh0z6vhq