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.
There is, exactly because png is made for strict rgb colorspace. Especially today when videos can be in HDR and with all kinds of color correction shenanigans, so which you won’t get back once you try to put the PNG back into the video.
But I’m not a video editor, so I don’t know what still format is best suited for this. I imagine real editors can deal with it, and for regular people who just make screenshots for memes, it’s good enough. As I said, png is still a good enough format, but let’s not use it for stuff like converting webp photos for further sharing.