I'm working on a portfolio, and I had an idea to add a section saying:
"My work has been seen by this __ many people."
In order to do this I have settled on using ShowMyStats, but in order to get that stats, I need to add another Google Analytics tracker to all the websites I manage. Is this possible? I've seen something answering this question here on stackoverflow, but it didn't work. Any ideas? All help appreciated.
It's best to use GTM to manage your ga trackers/properties. It becomes a trivial task that way. Here is a good article that goes quite deeply into the matter: https://www.simoahava.com/gtm-tips/send-google-analytics-tag-multiple-properties/
Another concern here is that it seems unlikely that an extension like that requires a new property. Why not just feeding it your existing property?
Your older question's accepted answer actually answers the question pretty well. Provide your debugging and fixing efforts for us to be able to move forward.
Finally, Google is deprecating GA UA, so you probably want to stop doing it for UA and start implementing it for GA4, which makes your code snippets obsolete, but also makes a good case for using GTM, since switching from UA to GA4 via GTM is a lot easier than via code. GTM tends to do its best to abstract the code from the users while still allowing liberal code injections.