How can I exclude (not delete) a transaction which doesn't appear in my bank feeds, but shows up on P&L, COA, etc. Can the transaction be excluded other than in bank ac?

Hello there, Zac.

Since it shows up in your Profit and Loss report and also in your Chart of accounts, it's possible that the transaction has been accidentally categorised in your Banking tab. You'll want to check the Categorised section inside the banking tab to verify if this is the case. I'll write down the steps below to get you going:

1. Access your QuickBooks Online company.
2. On the left navigational bar, go to the Banking tab.
3. In the Banking page, go to the Categorised section.
4. Locate the transaction, and then click Undo.|
5. You'll then proceed to Exclude the transaction.

Now, if in case the transaction doesn't appear in the Categorised section, it only means one thing. The transaction's been entered manually inside the company file and not through bank feeds. In this situation, please know that you don't have the option to exclude it. You can only Delete the said transaction.

Moreover, here's an article in case you'd like to modify your business report and highlight other aspects of your business: Customise reports in QuickBooks Online.

It's been a pleasure to have you here today, Zac. Feel free to mention me in the comment section if you need more help with this. I'll make sure to get back to you as soon as possible so I can provide further assistance.

I can provide additional information about excluding accounts, zac. 

You can make accounts from your Chart of Accounts (COA) inactive. It works like excluding them. Making an account inactive doesn't remove its transactions. Transactions associated with any deactivated (deleted) account stay intact.

Here's how to make them inactive:

1. Go to the Gear icon (⚙) and select Chart of Accounts.
2. Find the account you want to delete.
3. Select the Action dropdown and click on Make inactive.

For more information about making an account inactive and making it active it again, check out this article: Make an account inactive on your chart of accounts in QuickBooks Online. 

Here's how you can add a new account to your chart of accounts that will appear in your reports: Add an account to your chart of accounts in QuickBooks Online. 

Let me know if you need further help with your accounts. I'm always glad to help in any way I can. Have a great rest of the day!