Bastion or Doom tbh. Doom's requires you to already be very weak to ever die to it, assuming that it's not combo'd with a Mei ult or something. Even then, there's still such a high chance of surviving it....
Bastion's can sometimes arguably be a downgrade to the insane consistency of his turret mode. (Yes, it is overall better, but the fact that it's even sometimes worse than his base form makes it really underwhelming)