The issue I see with these theories is that this idea of inherent value they all arrive at is very abstract in a way. What does it even mean for something to have inherent value, and why is it wrong to destroy it?
Another problem is that we talk about destroying life without even fully understanding it in the first place. What if life (in the sense of consciousness) is indestructible?
The way I see it, people accept that life has some inherent value because our self preservation instinct tells us that we don't want to die and empathy allows us to extend that instinct to other living beings. Both are easily explained as products of evolution, not rational or objective, but simply evolutionarily favourable. All these theories are attempts to rationally explain this feeling, but they all inevitably fail, as they're (in my opinion) trying to prove something that simply isn't objectively true.
Anyways, I feel like even if you accepted any individual theory that seems to confirm our current understanding of morality and stuck with it fully, you would come to conclusions which are completely conflicting with it. For example in the case of utilitarianism, you could easily come to the conclusion that not donating most of your money to charity is immoral, as that would be the course of action which would result in the largest total amount of pleasure.