^^A lot of that really comes down to the "technological assumptions" made about how AI works in the setting in question; still, it's self-evidently the baseline that long as the computer core housing one is intact the platform carrying it around is readily enough replaceable.
And yeah a combat model is going to have hardware surge protection and whatnot up the wazoo already to avoid frying from damage-related power spikes and similar inevitable disturbances in its own systems...
You seem to have some rather odd ideas about robots, AI and the like in fiction though. They can certainly be used for far more - and far more sophisticated storytelling - than merely showing off their relative robustness compared to squishy organics! Existential ruminations tend to feature prominently for fairly obvious reasons - and the irrecoverable destruction of a sentient machine not being meaningfully different from the death of a living being is certainly in itself a poignant statement about such questions, whatever the competency of the writing now might be.