In a situation like that, don’t let ‘em get close.
There are learnable and usable tactics to stay far enough away from them, even as they are pressing.
Of course, if they press you, you may have to actually display or get ready to display.
“I don’t want to have to shoot you, but I’m armed, and if you take another step toward me, I will consider it a deadly threat.”
Well that’s certainly playing fair.