On a really steep hill, an automatic will not stop the car rolling back – well, that is what happened to me many moons ago driving a hired automatic.
Many manual cars are now fitted with an electronic handbrake (although I don’t like them, mostly due to lack of my experience in their use), my understanding is that they will not release until there is sufficient drive to the road wheels to stop the vehicle rolling back. If your issue with manual cars is hill starts – then a manual, with an electronic handbrake maybe for you (after you have mastered the technique of its use).