what would they be?
do you mean in sense of lossy or lossless? if so, in theory both webp and avif could have lossless photos, but i do not think they are designed for that (think in terms of their backrounds, they are kinda like a single frame videos. and usually you only have lossy video).
jpeg xl in theory aims to take job of both jpeg and png (it can handle lossy as well as lossless). In theory, we (as in all of computing and media people) decide to back on jpegxl, we could potentially just have 1 format, and accordingly 1 library which provides support. but that is just a dream i do not see happening. google essentially paralysed jpeg xl by removing it from chromium , and that is the largest userbase.
almost all other big companies want to use jpeg xl. meta, adobe, intel and others. the main benefit to them is reduced bandwidth cost (for exactly same data, jpeg xl can be ~20% smaller than jpeg), and jpeg can be losslessly translated to jxl, and even for backwards compatibility, reverse can be done on client end. but without chrome, no web developer will adopt. if web people do not, the demand for format would be extremely small, no hardware manufacturer will include hardware support (your gpus have "special" stuff for almot all codecs and formats, but that is not the case for jxl for now), so jxl operations currently are slow, so end user might not even be motivated to use (other than space savings).