Depends on what you spray. Depends on how you make that noise.
I’ve always considered making lots of noise and even bear spray as the equivalent of a “soft kill” in naval warfare parlance, the equivalent to electronic spoofing. Whereas, lots of well-aimed lead downrange is the more believable hard kill. Yes, I understand the problem of killing a charging bear, but a charging bear isn’t going to be deterred by a bit of spray or noise. YMMV.
Shot placement.
With good shot placement bear die as quickly as other animals.
I have shot a fair number of them.
Depends on what you spray. Depends on how you make that noise.