This seems rather optimistic to me. There are days when I count myself lucky to be able to debug my own code. And it's maybe about seven orders of magnitude less complex. And has comments. And unit tests.

I'd be willing to bet that once we've achieved the ability to scan and simulate brains at high fidelity, we'll still be far, far, far away from understanding how their spaghetti code creates emergent behaviour. We'll have created a hyper-detailed index of our incomprehension. Even augmented by AI debuggers, comprehension will take a long long time.

Of course IAMNAMSWABRIAJ (I am not a mad scientist with a brain in a jar), so YMMV.