Unfortunately I cannot make real recommendations for Russian learning for non-native speakers, as for me it is simply the native language and stuff just magically makes sense. I quickly looked over the book you listed, it looks to me to be a million times better than whatever you would get out of Duolingo. It is actually the perfect way to do grammar imo, you get grammar lessons along with small injections of vocabulary and all the big grammar topics seem covered. I would work on it and supplement it with maybe some basic Russian media(as the vocabulary inside doesn't seem perfect for daily interactions), but yes this is a good resource. I will warn that to me at least Russian seems like one of those languages that will be very hard to learn without immersion.