I have had a lot of fosters, rescues, dogs for training and dogs of my own.
Plenty had aggression or aggression issues.
ONE I decided to euthanize. A dog I took in as an adult. She had already killed a dog and another small animal, cat I think. And would go after children with the same "look." I worked with her for about 8 months. She had never bitten a child, but IMO only due to good management. I would not chance it with my daughter, and did not feel comfortable re-homing so took her in and held her head.