QR Code reader failure rate to high - QR Reader w/dblpass still fails to read pdf QR code

Version 19.0.4.0
We still are experiencing high rates of failed barcode reads.
We are specifically using the QR reader and utilizing double-pass on fail. The pdfs are scanned at 600 dpi.
Using your Winform Barcode reader demo won't recognise the barcodes either.
Up to this point, we've not been very satisfied with the error rate, when our free phone app reads the barcodes every time.
Please find attached PDF samples where the barcodes cannot be read and our main snippet of code that calls the LeadTools engine.

Hello,

Do note we provide a wide variety of image preprocessing functionality in order to improve the recognition accuracy. I was able to recognize the images you attached in the LEADTOOLS Barcode demo installed alongside the SDK:
C:\LEADTOOLS 19\Shortcuts\Barcode\.NET Class Libraries\Barcode Demo

After applying the AutoBinarizeCommand, I was able to recognize 9, 10, and 18.
https://www.leadtools.com/help/leadtools/v19m/dh/po/autobinarizecommand.html

I was able to recognize 17 and 19 after applying a MinimumCommand with a sample size of 2 to dilate the pixels. Note this is accessible in the Barcode Demo: from the menu bar, Preprocessing -> Noise Filters -> Minimum.
https://www.leadtools.com/help/leadtools/v19m/dh/po/minimumcommand.html

I have attached a zip file of the images with this preprocessing applied that I was able to recognize.