It's not supported by either Chromium or Firefox, which is part of the issue (Google basically decided against it with arguments that are much better suited against WebP, which they pushed some years ago).

There aren't that many static image codec comparisons, for example there is https://giannirosato.com/blog/post/image-comparison/. https://afontenot.github.io/image-formats-comparison/ doesn't even include WebP because the test suite uses features unsupported by it (YUV 4:4:4). In the ones I do find, WebP usually wins against good JPEG at low bitrates, but loses on high bitrates because of the blurriness issue. They both get beaten by JPEG XL and AVIF. Which one is better probably depends on whom you ask. The before linked comparison prefers JPEG XL by a slim margin, https://tonisagrista.com/blog/2023/jpegxl-vs-avif/ strongly favors JPEG XL.