Hi there,
….I got some crashed in some of my featured post images.
Can you share any error logs? webP should work with WPSP assuming your WordPress site allows for it. WPSP doesn’t handle media file permissions.
Here’s a sample page with a WPSP having a post with it’s featured image as webP format. https://dev-generate-press.pantheonsite.io/1671-2/
The webP image here is directly uploaded to the media library and then served by WPSP.