In the  sales order form view,  I can manually click "Add a product", select the product and then click "Add a note" and manually populate the content of the note.

I would like to be able to automatically add a pre-populated note field as soon as the product_id is selected, but because the note is a different sale.order.line record, I'm having a difficult time getting it to work with @api.onchange()

Any thoughts on how to accomplish this?