Technically this is linked to the ability to simulate our universe efficiently. If it’s simulable efficiently then AGI is possible for sure, otherwise we don’t know. Everything boils down to the existence or not of an efficient algorithm to simulate Quantum Physics. At the moment we don’t know any except using QP itself (essentially hacking the Universe’s algorithm itself and cheating) with Quantum Computing (that IMO will prove exponentially difficult to harness, at least the same difficulty as creating AGI). So, yes, brains might be > computers.