For cutting through the sternum or the pelvis bone, I use a small saw, it works wonderfully on any game, all the way to moose or bison. Either a specialized one, or even better, as I discovered a couple years ago, a general purpose Silky Saw F180 folding, which is a pull saw.It never occurred to me to break through a big hard deer pelvis with a jack knife. My 45 year old knife is clean and sharp after 100 or more deer, I have no complaints. And no judgement.
In the past, I also used a sturdy knife (e.g. my Jääkäripuukko 140) for deer sternum, and a small hatchet for the pelvis bone or moose sternum.
But a small hand saw is way better.