I base the stats off of the Monstie stats in Monster Hunter Stories 2 and then apply a basic formula to them to make them work in my game, so I don't want to change them if I can avoid it.
The Anjugsass is mostly a challenge right now because she's a rank above what you should be fighting, in the full game you'll be better equipped to take her on.
Also I'm working on a system overhaul for the next update, part of that will be increasing the Hunter's HP but also adding some more randomness to the combat, so it should hopefully end up as a fairer challenge.