Blockchain wallet or blockchain.com wallet is most popular cryptocurrency wallet out there and recently it has rolled out numerous features such as ability to trade one cryptocurrency for another. They have also added ability to earn interest. This account is called Interest Account.
And there is an exchange wallet feature as well. This one has been renamed to Exchange account.
The main wallet is now called Private Key wallet. This makes sense blockchain wallet allows users to manage their funds on their own by providing them access to private key. Make sure never to share this private key with anyone as anyone with private key has full access to your funds.
To access private key of your bitcoin, ethereum, bitcoin cash and Stellar Lumens wallet, you would have to access blockchain wallet on your desktop. Alternatively, you can fire up blockchain.com on your iPhone/android phone and switch to desktop mode.
Keep in mind private key of Ethereum wallet and USDT wallet is same as USDT being used on blockchain wallet is an ERC20 token so private key of ethereum = USDT wallet.
In short, your Wallet is now your Private Key Wallet. Your Trading Wallet is now your Trading Account. Your Interest Account will remain your Interest Account. Your Exchange Wallet is now your Exchange Account.