Using the context menu option, you can  disable a Microsoft Edge PDF:

• Open the File Explorer programme.
• Navigate to the folder containing a PDF document.
• Right-click the.pdf file and select 'Save As.'
• Select the Choose another app option from the Open with submenu.
• To open PDF files, choose the new default programme.
• Quick tip: If the app you're looking for isn't on the list, select More apps. Alternatively, you may use the Look for another app on this PC option to manually locate the software. If this is the case, you'll need to choose the PDF application's.exe file.
• Select the option to always use this programme to open.pdf files.

Read More: How do I add text to PDF files using Microsoft Edge?