Is there an optimal caliber to carry while hiking?

I’m an avid hiker in northern Colorado and the last couple years I’ve been solo hiking, and planning on solo backpacking. I have felt safe enough with just bear spray, but there’s been a couple of trails lately that have had mountain lion tracks following along the trail. I’ve also had encounters with black bears and moose, and am planning on spending some time in Montana. I understand that if a mountain lion was stalking me, I wouldn’t have time to get a couple shots off before they pounce, but I’d still feel a lot more comfortable with a pistol to take out with me. I’ve done a good amount of research and there doesn’t seem to be a consensus on what caliber is best. I’m debating between a 10mm, .38, and a .45. I’m okay with something with more punch if it means less bullets, but I understand that my aim wont be the best if I have a charging animal 15 yards from me. I’m also not concerned with weight. I would really appreciate some advice and hear about what other people carry.