I don’t know what a .webp file is but I don’t like it. They’re like a filthy prank version of the image/gif you’re looking for. They make you jump through all these hoops to find the original versions of the files that you can actually do anything with.
Wow, doesn’t surprise me that Adobe does not support it. They still don’t support full screen or native dark mode on macOS in After Effects. Guess poor Adobe can’t be bothered to update basic functionality.