Why is there not an option to mark an account as closed under bank accounts for accounts that are closed and without internet access?

In QB Online, mark the account as inactive and then when you display the Chart of Accounts including inactive accounts, it displays as deleted. On the Charts of Accounts screen at the right, you will see "View Register" , click on the drop down and select "Make Inactive"  If you click on the Gear symbol at the top of the Chart of Accounts you will see several display options including "Other: Include Inactive"   If you no longer want to see inactive accounts, make sure to uncheck this box.

*Sorry, just saw this is QB Self-Employed version, so not sure if it works the same.

I can share details about your connected bank accounts in QuickBooks Self-Employed, @K211_2.

May I know if you're trying to turn Off bank account in your QuickBooks Profile to hide the closed bank account? If this is the case, you won't be able to close or mark your closed bank account inactive or Off since QuickBooks Self-Employed is accessible through the internet that has your bank authentication. We save your QuickBooks data in a secure server accessible via an internet connection.

And if you wish to maintain the data you have from a closed bank account, you might want to remain it as it is or export them to have a copy of those banking entries.

1. Select the Transactions menu.
2. Make sure to choose the correct account in the Account drop-down arrow.
3. Then, click the appropriate Type and Date
4. Select the Export icon.

I also suggest contacting our QuickBooks Self-Employed support to see if they can mark your bank account inactive using their tools. One of our representatives can pull up your account in a secure session. 

Otherwise, you'll have to delete a closed bank account. Please know this method is irreversible and will remove all transactions and any special calculations. I'd like you to check this article to learn more information: Delete bank and transaction data in QuickBooks Self-Employed.

Additionally, you may want to enter older transactions from your other banks. You can take a look at this article for the detailed steps: Manually import transactions into QuickBooks Self-Employed.

I'm looking forward to your reply. You can add more questions if you need more assistance. Have a pleasant day ahead!