Wanting to know how to unlink the bank account I linked....

Hello there, @tmsunny.

Let's go to the Banking menu and edit your bank account info so you can unlink it to online banking in QuickBooks Online (QBO). 

When you unlink or disconnect an account that's connected to online banking, this will stop QuickBooks from downloading new transactions. Then, deletes those that still need to be categorized in the For review tab. With this, I encourage you to add and match all the pending transactions on the Banking page before doing so.

Once you're ready, follow these steps to disconnect an account from online banking:

1. Go to Bookkeeping, select Transactions, then Banking.
2. Select the tile for the bank account.
3. Click the pencil ✎ icon, then select Edit account info.
4. Select the Disconnect this account on save checkbox. Note: If QuickBooks is downloading new transactions, you won't see this option. Wait a few minutes for the update to finish and try again.
5. Click Save and Close.

You can reconnect the account anytime to start downloading transactions again.

Please feel free to read this article for more details: Disconnect accounts connected to online banking in QuickBooks Online.

Also, I encourage you to reconcile your accounts in QBO regularly (every month). This helps you monitor your income and expense transactions and detect possible errors accordingly. You may want to check out this article as your reference to guide you in doing or fixing a reconciliation: Learn the reconcile workflow in QuickBooks.

Let me know if you have other banking concerns or questions about managing transactions in QBO. I'll gladly help. Take care, and have a great day, @tmsunny.