Again, too many to answer but here is an interesting article on one strain (there were more than one) of Shingon Pure Land thought, as conceived by a medieval master named Kakuban (pdf file):
https://nirc.nanzan-u.ac.jp/nfile/2291
This book by a Japanese Shingon priest is also highly recommend as a basic overview. It's also quite a bit more expensive than it was when I came across it in the early 1990s.:
As for the Huayan School, Shingon founder Kukai ranked the Huayan Scripture second-highest to his own esoteric scriptures, so he had respect for it. I don't know that one can speak of comparative cosmology between the two systems; Shingon thinks of reality in its own way and I can't do justice to the Shingon worldview in this kind of limited format.
" I would like to know the soteriological goal of Shingon.": Shingon speaks of
Sokushin Jobutsu, or "Buddahood in this very body." Through manipulation of body, speech, and mind (using mantras, mudras, visualizations, ritual implements, altar spaces, and mandalas), one can become one with a Buddha or Bodhisattva through ritual technique. Shingon also has rituals for more worldly goals. There are a large number of rituals, mandalas, and esoteric texts.