Narcissists are pretty forgiving of themselves.
But you may be very right.
You’re right. It’s a myth that narcissists actually have low self esteem. They don’t. They fully believe their own hype.
That said, they are very big on Image Management. A person with NPD could potentially take his own life if his image were damaged badly enough. At least in theory.
Narcissists are not generally high suicide risks. They do all of their damage to others. However, NPD can be comorbid with other disorders, eg despression. That could be a suicide driver.