"According to my benchmarks, JPEG XL also outperforms AVIF at quality settings very much suitable for the web, especially if you compare them at same-cpu-effort encoder settings. If you have data that says something else, could you please share it?"
A bad news for you; it was made by Google, partly (Google Zurich and Cloudinary). It wasn't adopted probably because it didn't originate from the Google Chrome team.
I really hope JPEG XL wins the next generation lossy image codec war, for the killer feature of being able to losslessly convert my back catalog of JPEG photos to JPEG XL photos.
JPEG XL still has too poor browser support to be taken seriously although I hope Safari's move in the most recent version will apply more pressure on Google.
Jon Sneyers (main JPEG XL designer) :
"According to my benchmarks, JPEG XL also outperforms AVIF at quality settings very much suitable for the web, especially if you compare them at same-cpu-effort encoder settings. If you have data that says something else, could you please share it?"
https://twitter.com/jonsneyers/status/1666062661585367042