I’ve heard femoral arteries (inside thighs) are a good target.
Slashes are very effective. Inside wrists, elbows, armpits, behind the knee, Achilles tendon. Disable your opponent and you can walk away faster than he can hobble after you.
A Sargent Major recommended slashes to the face, because the blood would be dramatic, for psychological effect.
A good friend used slashes to the muzzle as a defense to dog attacks in Russia. He said they worked well.
Better yet, feint at the chest and when they lift up their arms to back away, slash under the back side of the bicep. Will die every time.