I read the book fifty years ago when I first started to investigate Buddhism. As you wrote the book is a nice introduction. As a secular Buddhist I’m agnostic about metaphysics and claims about an afterlife but the baggage of him living in the time of Brahmin dominance can be ignored in my view since it is just the Zeitgeist of his times and not an essential part of his message.
Reading Buddhist cannon is a bit dreary since it is a capture of an orange tradition which means it’s repetitious so the book is a place to start for most.
You might like this if you can deal with the repitition I mentioned. It is a departure from doing things because of some reward or punishment in an afterlife and just addresses doing what is good and beneficial without belief in the unknowable.