Welcome to the Community space, @Kirkk. I'll share an insight about splitting downloaded transactions inside QuickBooks Online (QBO).

In QBO, know that you can only assign or split downloading bank transactions to multiple accounts. However, there's a workaround to get you out of this situation. You can split them but not in the banking page. I'll input the whole process below to get you started. To begin, these are the steps:

1. Access your QuickBooks Online company.
2. On the left navigational bar, click the +New button and then select Invoice.
3. Enter all the needed information in each field, and then click Save.
4. Click Receive payment, and then input the amount of the invoice.
5. Once done, Save and close.

After receiving the payment for the invoice, you'll want to proceed to the bank deposit. When in the bank deposit tab, select the amount you want to include when depositing to the account, and then in the Add funds to this deposit section, enter the appropriate amount to assign to your account. Doing this allows you to split the funds between an account and an invoice.

You can refer to this article for further guidelines: Record and make bank deposits in QuickBooks Online.

Once everything is ready, follow these set of steps to ensure they're recorded correctly inside your company:

1. Access your QuickBooks Online company.
2. On the left navigational bar, go to the Banking tab.
3. Locate and access the downloaded bank transaction, and then click Find other matches.
4. Enter the appropriate date.
5. Choose the correct transaction to match.

In addition, here's an article about generating reports inside QBO to ensure your data is accurate: Run reports in QuickBooks Online.

@Kirkk, it's been a pleasure to have you here today. Feel free me mention me in the comment section if you need further assistance with this. Take care!