Not your keys, not your bitcoins.
You already have a cold wallet, and let's think why you decided to use that cold wallet? To keep your private keys offline, secretly. And now you want to import it to Coinbase wallet?
It is conflicting activities.
Just don't.
As he is referring to Coinbase custodial service, it is not even possible. I know you know that.
What is in my of TadpolesIsAWinner is not about importing the private key into a custodial exchanges. What image wants is all means he can safely sell his coin on Coinbase.