If you no longer want an estimate attached to a deal, you can remove it at any time.
Open the Deal page and locate the linked Estimate.
Click the "..." (menu) and Remove Association.
The Estimate (and any invoices linked to it) will no longer appear on the Deal page.
💡 The Estimate and Invoice(s) are not deleted — they still remain visible under the Estimates and Invoices pages in your account.