I believe I found a workaround based on the sources in the question link that was mentioned in my opening question.

Entering the following in terminal followed by enter will make changes to ~/Library/Preferences/.GlobalPreferences.plist (this is a hidden file revealed with command + shift + . if manually browsed to in a Finder window via Go > Go to Folder)

defaults write -g AppleICUTimeFormatStrings -dict-add 1 "hh':'mm':'ss' 'a"

After force-quit restarting Finder, the desired time format with seconds is now working perfectly.

I believe I found a workaround based on the sources in the question link that was mentioned in my opening question.

Entering the following in Terminal followed by Enter will make changes to ~/Library/Preferences/.GlobalPreferences.plist (this is a hidden file revealed with Cmd+Shift+. if manually browsed to in a Finder window via Go > Go to Folder)

defaults write -g AppleICUTimeFormatStrings -dict-add 1 "hh':'mm':'ss' 'a"

After force-quit restarting the Finder, the desired time format with seconds is now working perfectly.