Seems like the original document was produced from a scanning device or software (I may be wrong though).
I ran the Accessibility Checker tool and found too many failed tests. Some of the most serious problems had to do with custom embedded text that hasd no propper identification as for me to be able to figure out what to embed if I wanted to choose the PDF Optmimizer (which I did as my second attempt to fix the, after using the Preflight tool --PDF Fixups of the Print Production Tool, which also failed for me).
So, The original PDF that you shareed had too many page structure issues, no tagging, among other issues.
In the end what really worked for me was to export the PDF to a TIFF image file. Then Used the Create PDF from File, and created a whole new PDF document from these .tif image files.The next step, I used the Combine Files tools -->>> "Add Open Files" (all the new PDFs were opened in separate tabs after the image to PDF conversion, so you have to combine them as single binder PDF file).
Last, I obtained a beautifully looking PDF using these method, which also ran the PDF Optimizer and performed a Searchable Image task which ultimately allowed me to export to MS Word file format directly from Acrobat with almost identical results.
I say almost because for some reason the blue border frame in that document kept coming out as black in the export (no matter what I tried). Si I manually changed it to its original blue theme color in Word, and also perform a grammar check.
Here are the resulting fixed files: