The following program did the job:
http://www.a-pdf.com/faq/how-to-decrypt-pdf-security.htm
The download trial for it worked. Purchasing the full version at $27 which I think is reasonable for a convenient tool that works.
Update
There is also ilovepdf.com which is a freemium service in that it has some free options that may cover those doing a similar task as me, depending on the quantity and other conditions of using the free version. Pricing information if requirements are not offered by the free service are here: https://www.ilovepdf.com/pricing
No affiliation. The above came from a suggested edit from user Rythorian Ethrovon Their affiliation not known. I included the reference to ilovepdf as an update to this existing answer, to add to the original, rather than a complete replacement to my existing answer.
My response on their edit suggestion is: 1. don't suggest an edit that entirely replaces the original answer that still had the same useful value. 2. Instead of posting your solution as a edit suggestion, post your solution as an additional answer - you can do that! Or as a comment.
All that said, my preference is for my original answer in a-pdf because it is an application, which, as far as i can tell, handles all my pdf file data locally, rather than as a cloud service where I may have less control or understanding of how long my pdf files would be stored in the cloud and if they would be used for purposes outside of my task. But cloud services can suit many, including me, jsut depends on the specific circumstance.