JPEG-XL is not really any better than WEBP. You need to be using AVIF "significantly smaller", just a shame that Google's online AVIF compressor sucks so-much (Wrong compression mode and uses the AV1 default artifact blending (Chroma Sharpening which is not really sharpening or even just for Chroma but actually sets the artifact blending. 0 is default for AV1 and tries to hide all artifacts, increasing to 3 which shows all artifacts).