There would be good to have some flashbacks of Theta's first hunts that didn't go that well. The story is all there in visual storytelling, she is covered with scars, must have lost her leg at some point. It shows that her quest isn't a walk in the park, she just is experienced and have proper gear at the point we first see her. But because we never saw that journey, i can see why for some people her skills and wins may seem undesrved.