I have asked Coinbase Wallet this questions numerous times never getting an answer that works.
What answers did you get? Maybe you are doing something wrong.
Celsius is just an ERC-20 token. Should be easy to dump to ETH and deposit to any exchange that will allow you to dump it to $ and withdraw to US bank account (linke binance.us, or coinbase).
I would go with:
1- creace ETH wallet using metamask
2- withdraw cel to this wallet
3- use uniswap to dump cel to eth
4- deposit ETH to cainbase on binance.us
5- dump to $
6- withdraw $
Or use build in DAPs in coinbase wallet, find any DEX (not sure what is there) and dump CEL to ETH there.