The current feature tracking for AVIF and JXL is not complete. Implementation of AVIF does not guarantee support for HDR images (ie they may not properly render images with the PQ or HLG transfer functions requested in the CICP data for the image). For example, FireFox v105.0 renders these images extremely dark and Safari clips highlights in iOS 16.0. So they render AVIF images, but HDR AVIF images are not properly supported.

Given legacy file formats like JPG do not support HDR, it is very important to have a clear understanding of browser support for HDR images. AVIF is properly supported in Chrome (and looks amazing with a 1000+ nits screen like the M1 MacBook Pro).

For example/test images and more information on HDR display, see https://gregbenzphotography.com/hdr/.
Note, this name is confusing and has nothing to do with the "HDR" many people know. This is a different technology which requires supporting display hardware for brighter pixels, and is already available on most Apple devices sold in the last 4 years.

Note: it would also be very useful to track HDR JXL support. Chrome already provides proper support if you enable a developer flag. Adobe Camera RAW v15 supports exporting of HDR images as JXL files. See the 9:20 point in this video for a demo: https://gregbenzphotography.com/photography-tips/acr-15-adds-high-dynamic-range-output/