Just going off a hunch but I think this might be Youko Furuya's work. The way Taichi looks (unless that's just the usual Asanuma CAD work tricking my brain) and moves reminds me of their work on the 4th ED.

EDIT: https://twitter.com/yafuuw/status/1439424497279406085
It's Furuya after all! They even did the Nigen.