I have read that even rifle rounds have ricocheted off a bear’s skull.......................
I have read that also.
I think it is mostly a myth, based on missing the brain.
It is possible, if aiming directly between the eyes, to hit a tiny bit high, and miss the brain.
Bullets that hit on a very oblique angle can be deflected by bone.
There have been several cases where .45 ACP pistol bullets have been deflected by human skulls. Sometimes the bullet goes under the skin, travels part way around the skull, and exits.
The bone between the eyes of a large bear slopes at a very oblique angle. It is tough and strong.
The nose channel runs directly to the brain.
Moral: Take your .357 magnum instead of the .22.