HP Device Manager seems to not recognize the PPD file

Am trying to install an HP Officejet Pro 6970 using the HP Device Manager. It seems I am having issues referencing the correct PPD file.

I can detect the printer on my network, but when I select the PPD file, nothing happens, and the HP Device Manager indicates "no PPD file found". The ppd.gz file is there, and I have unzipped it (hp-officejet_pro_6970.ppd). I can highlight that, but when I do so, and return to the next page, the HP Device Manager still says "no PPD file found".

What am I doing wrong?
Screenshot_20200618_013000

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