I added new transactions (expenses, transfers, deposits) to my checking account in the Chart of Accounts, but when I go to the Transactions tab, they do not show up

Glad to see you here in the Community space, usereric-jentoftherr.

The transactions showing on the Banking page are newly downloaded transactions from your online banking account and imported data. This section allows you to review, add, find a match or transfer these bank transactions.

As for manually added transactions, you can view them via Sales Or Expenses page, depends on what type of transaction entered.

For more information about categorizing your bank entries, see this article: Categorize and match online bank transactions in QuickBooks Online.

Here's also an article which you may find helpful in the future: Reconcile an account in QuickBooks Online.

Feel free to get back in this thread if you have any other questions about QuickBooks Online. I'll be around to help you out.