"There's no text to convert in this file"

A PDF made from a scanner or a phone photo holds a picture of each page, not the words themselves. Tools that read text, such as PDF to Excel, have nothing to work with. You can tell by trying to select a word in your PDF reader: if you can't, the page is a picture.

What to try

Open OCR PDF, add the scanned PDF, and choose the document's language. It adds an invisible text layer. Then convert the searchable PDF it gives you. PDF to Word keeps scanned pages as pictures, so you can still use it without OCR, but the text won't be editable.