If you are troubled by the thought of what a T rex did to a Triceratops 69 million years ago, how do you feel about modern wildlife reserves, where lions, wolves, bears and other predators kill prey animals whenever they need a meal? Would you prefer a world with no wild carnivores at all?
Olaf Stapledon's excellent book Star Maker suggests even the creator of the universe may be "limited... by certain absolute logical principles". Which is similar to your statement that carnivory may be "an inescapable fact of evolution" — a fact that not even an omnipotent God could avoid.
Perhaps fear and pain are also inescapable facts of evolution? Maybe they are Nature's way of impelling animals to avoid dangerous situations, such as getting pounced on by another animal; and to struggle as hard as they can to break free if they do get pounced on?
I know that a world full of "philosophical zombies" seems logically possible to some philosophers; but how do we know whether it would work in practice? And how would we recognise a world like that if we saw one?
I'd also mention that Nature, or the Star Maker, has equipped humans and other animals with endorphins — substances which operate as natural anaesthetics. So the suffering of a human or a Triceratops does not simply escalate without limit as the physical trauma gets worse.