You've got 4 Amazon reviews and 1 Goodreads review.
To me as a potential reader that basically says that you've got no reviews worth noticing. That might sound harsh, but the reality is that having so few reviews is not enough for them to carry much weight as they could so easily be "friends and family" type reviews. I tend to not pay a vast amount of attention unless there are negative reviews and also if there's at least over around 50 reviews when Amazon/goodreads is the prime source of reference (ergo when its not referred to me by a friend/ an author I already like etc...). Even then I've had hit or miss results until reviews jump into the 100 and greater in positive reviews.
So more reviews is a thing you need, have you sent out copies to review blogs/websites/vlogs (youtube) etc..? Have you joined up to becoming a "Goodreads Author"; have you any physical stock and are you doing signing events at local book stores? Have you been publishing short stories in writing magazines (perhaps even seeding a short story set in this world in that magazine with a follow-up note that its part of a soon to be published world and story The Witch's Box?).
What about your beta readers? How many did you have and did you ask any to drop you a review as well? What about promotional events? Did you offer out a dozen copies to people that you've networked with etc...?
Marketing is about getting attention on yourself an it IS hard. It is going to cost and it does take a significant time investment; plus its a rat race with a lot of other authors in the same race all fighting to get noticed.
On the subject of your reader comments :
"That was a very good read, by some margin the best I've read by this author."
"...the execution of teaching Maihara about life is fabulous."
"This isn't the usual genre I'd read but I really enjoyed the book."
"This is a well-structured, fun read with some incredibly well done battles and an intriguing magic system."
Honestly I'd drop ALL except the last. The first isn't positive enough and suggests that you might still have a ways to go; the second is not really of any interest in my view; the third has no context and is sort of casual. Only the last is actually grabbing my attention in anyway by saying that there's battles, magic and that they've clearly enjoyed it - there's and "energy" in that short quotation that's missing from many of the others.
That said all four are also not attributed to anyone. Who said those things? Was one by your family? Who your reader comments are from is almost as important as what is said. When you see big publishers doing this they always attribute and they always attribute to a known entity. Most often another author within the same publishing house - GRRM saying that he loved your book carries weight. Dave loved your book carries none and "I loved this book" even less. Another option is to quote reviewers - be they online or newspaper etc.... Again its providing someone of a known value and quantity and honestly also trading off their name, in part, to help get attention to yourself.
I agree with the part regarding maps mentioned above, you might want to check out this thread
Fantasy Map Creation kit! where there's some mapping software that would ideally suit your desires for creating a professional looking fantasy map whilst not being gifted with great art skills. Little touches like the quality of the map do make a difference to a readers early impressions of a book.