> JpegXL will be the best of all worlds choice in a few years when software support is good.
Where is the software support lacking other than the browsers at this point?
I suspect there are a few 10s of thousands of websites that still only accept Jpeg (as a user upload). Some accept PNG. Few accept HEIF, almost none accept JPEG-XL
The encoder currently isn't using a lot of format features like curves or layers (which would partially also require deeper integration in for example Photoshop to pass such information to the encoder).
File explorer support, thumbnails, local image viewers and editors, import into other media software like slideshows, video editors, 3d modeling software, etc etc.