No Apple tools generate JPEG XL by default. You can, of course, export as jxl on newer OSes, since it's built in, but it's not a default. iOS devices still use

No Apple tools generate JPEG XL by default. You can, of course, export as jxl on newer OSes, since it's built in, but it's not a default. iOS devices still use HEIC as the default "new" image format, but convert to regular JPEG when shared with services which don't support it.