So I received a follow-up email from Standard Notes as follows…
“I’ve confirmed the details with one of the devs on the team. Indeed the decrypted content is in working memory, however, your initial assumption was actually correct. That is, the operating system is able to access the decrypted data while it is in working memory. Since it’s essential for the app to interface with the OS, exactly how the OS accesses and handles the app data and memory is unfortunately something out of our control. However, do rest assured that we’ve made the app as secure as possible in all areas where we do have control 
In case you haven’t done so yet, you may browse through our help articles on Privacy and Longevity in our help page, where we discuss certain topics on how the app keeps your notes secure in general, as well as the details of how encryption is applied on your data.”
Therefore all of the knowledgeable folks with us on here have pointed out some great loopholes that I did not know about before this thread and I thank you.
Bottom line if you’re using non-open source operating system’s there’s just no way to trust what they’re doing with your data anytime a so-called secure and private app is open and being used. I now even have serious doubts about Signal and Threema as to just how private they actually are?
Thank you again everyone!