Looks interesting, thanks. (Too bad, as one of the reviewers notes, “author has given up on theoretical physics and now runs a software development company specializing in lighting/shading routines for video games”...)
Anthony Lasenby, professor astrophysics and cosmology at Cambridge, is also absolutely still actively researching and publishing, all in the mindset of the GA4Physicists book. (See a recent (feb 2020) lecture of him here : https://www.youtube.com/watch?v=x7eLEtmq6PY&t=7s )
(GA4P is considered one of the few comprehensive and up to date treatments of geometric algebra, not just in physics).