https://squoosh.app/ has both avif and jpegxl if you want to try it out.
AVIF does not support recompression of JPEG files like Lepton, Brunsli, PackJPG, 7zip media layer (using Brunsli), and JPEG XL. AVIF works very well in the high density low-bit-rate compression. The flip side there is loss of detail.
https://squoosh.app/ has both avif and jpegxl if you want to try it out.