I can clear things out about the invoice and estimate added by System Administration.
Once you create recurring transactions, QuickBooks Online automatically creates them. Those transactions may have been set up to recur every 1st day of the month. That's why you're seeing these entries in the Audit log page.
You'll want to go to the Recurring Transactions page to verify the recurring template you've set up. I'm glad to walk you through the steps:
Go to the Settings ⚙️ icon, then select Recurring Transactions.
From the Action column of the transaction, select Edit.
Review the details of the template or edit it when necessary.