Cannot find or create the font ...
I know this same question/error's been posted a million times and has been around for at least a decade. There's a number of possible causes and fixes, but none have worked for me.
Essentially, I open a PDF (unknown who produced it or how much it's been modified since then), but on some computers I get the error "Cannot find or create the font 'ArialMT'. Some characters may not display or print correctly.", while on others, I get no error dialog at all, but some text is just white boxes while other text (even within the same word or even just a closing bracket (i.e., ']') shows up fine:

From digging into the issue, I understand that some version/variation of a font wasn't embedded when the PDF was created, but what I don't understand is why I can open the exact same PDF in various PDF applications and some of them are able to display the entire PDF without any issue. To wit:
Adobe Acrobat Pro DC (2021.005.20060) - White boxes
Adobe Acrobat Reader DC (2021.005.20060) - White boxes
Nitro Pro (13.31.0.605) - No problems whatsoever
Unfortunately, the individual experiencing this issue (in addition to me being able to replicate it) is basically required to use AAP and can't use anything else due to <waves hand around> "reasons".
I ran the document in question through PreFlight and of course it finds a host of issues (font name is not unique; font not embedded; font reverts to .notdef glyph; text cannot be mapped to unicode; etc.).
Confounding the issue even further, I'm able to open the PDF in question just fine in Adobe Acrobat Reader DC (in addition to Nitro PDF) on at least one other computer. O' Consistency, whyfor dost thou detest me so!
Ahem.
So my questions are thus: Am I essentially boned on being able to get Adobe Acrobat Pro DC to open this PDF without issue, or at to display everything correctly and, if not, why does it open (and print) correctly with Nitro PDF (of which I'm not typically a fan, but it seems a mite less ... complexified than AAPDC)?
Any advice/guesses/suggestions/etc.? (Many thanks for any help!)
P.S., I'm not able to upload the PDF in question as it's (A), company-sensitive info and (B), 401 pages, but I may be able to hunt down a similarly affected document that would be postable.
