Convert animated .png to .avif (+ to h.264, h.265, h.266, vp8, vp9, av1. don't work)

[andsofine]

As far as I understand there is no option to convert animated .png (aka apng) to .avif.

Also out of curiosity to find out if Shutter Encoder can convert animated png to some other video format I tried all options under h.264, h.265, h.266, vp8, vp9, av1.
But nothing appeared in the save folder although after each time it said “The process has been completed” without any error popups. I thought maybe Shutter Encoder doesn't have permission to use the folder. (I also tried restarting it). But that's not the case, because when converting to image formats (like .jpeg) the files are saved.

macOS, Shutter Encoder 18.5

[andsofine]

I should have clarified that by animated .png to .avif I mean animated .png to animated .avif.
Although it is probably clear from the context.