I am also curious what plans have the MS Edge developers with AVIF. Firefox supports AVIF by default now: https://caniuse.com/avif but no support on MS Edge side yet. On the other hand, Edge added experimental support for JPEG XL (enabled when --enable-features=JXL parameter is used to start browser). It is good to support JPEG XL too but will be the AVIF added too? Microsoft is Founding member of Alliance of Open Media, the community behind the AVIF format, so I hope AVIF will get more attention from Microsoft. On order to allow new, effective image formats (AVIF, JPEG XL) to be successful, we need support from browsers. These new image formats are huge progress compared to the traditional image formats from 20th century, they deserve to be supported.
For my tests, AVIF isn't a good option specially because it's too resources intensive for modest devices. Also, often I have to check batch converted images due to weird artefacts added to files. JPEG-XL is a safer bet.