Disregarding ethical concerns, how challenging would it be to artificially provide signals to nerves going to the brain and get output through other nerves? Wit

Disregarding ethical concerns, how challenging would it be to artificially provide signals to nerves going to the brain and get output through other nerves? With some kind of device like an ECMO connected directly to an extracted brain, the optical nerves connected to a computer somehow, and some fine motor control nerves connected back to the computer, a brain could operate completely outside of a body.