WebP image not created

Hi, I’m trying the plugin, specifically the webp functionality, but it doesn’t seem to work, or I don’t understand how it should work.

When I upload a jpeg image from the media library nothing happens, the image remains in jpeg and I think it’s the normal behaviour.
When I add this image to the page or article, it is not converted to webp, it always remains jpeg.

If, on the other hand, I load a .webp image from the media library, this image is also converted to jpeg. The same thing happens with sub-sized images, I find them both in webp and jpeg.

This webp functionality need some specific php modules to work?

In site healt i see no error about the webp module, WordPress 5.9 with php 7.4. and some plugin, this is a test domain.