First, examine the reasons that orders confirmed by Customers can't be confirmed for procurement at the same time and resolve them as much as you can (pricelists incorrect, Vendors not setup, reordering rules not configured, etc) to make sure you don't introduce an artificial delay in your process.

If you really need this step, you can interfere with the confirmation and stop Odoo moving Quotations beyond the QUOTATION SENT stage.

Leverage the Automation Framework and create an Automated Action that watches the state field and is applied on all records that move "into" the SALES ORDER state:

This code snippet checks WHO is doing the confirming.  If it is not an end User (uid = 1 is Odoo Bot), then the state is set to "sent" instead of "sale" and a custom field x_signed is set to True, allowing you to find Quotations that have been signed but not yet confirmed (you can also create a custom Filter to find them faster).

Please test this in your own database, this is an approach, not necessarily a complete solution.  There may be additional cases you have to consider.