You could use `git log -p` instead of `git log` so that the diff is included.

To navigate efficiently between the commits, you could pre-seed less with a regex that matches commit (and file) lines, so that "n" and "N" jump from one commit (or file) to the next, something like this

  LESS="-R --pattern ^(commit|diff) " git log -p

Delta[1] makes this convenient: delta --navigate.

[1] https://github.com/dandavison/delta

(Disclosure: I am the author of delta)