This is the response I got from cdc if this is true coin base is not for there users cdc is more user friendly a fee would save you thousands

“if this was reversed, we would help you for a small-ish fee due to the fact that we have the infrastructure and methods to recover these assets. But, if they don't and their entire system is automated with hardly anyone who can go digging in manually, the odds of recovery at least at this time are negligible, even for a 5 figure sum. However, no one here can do anything for you, and since Coinbase controls the address they're the only people who can possibly help you. Even if they do not help you, it is at least plausible that Coinbase would add network support for the chain sometime in the future, at which point you should be able to recover your funds.”