HERE'S THE SOLUTION:
In Google Analytics create a new property.
In the new property setup panel there's a link "Show Advanced Options" at the bottom.
In Advanced Options there's an option "Create a Universal Analytics property". Using this option will give you the option to either create both a GA4 and a UA id in which case it creates 2 properties and links them or you can just create a single UA id.
GA4 tracking implementation is in Beta and will eventually go and replace Universal Analytics (UA) as the measurement code for tracking via Google Analytics. There is going to be a lot of work involved as many big companies have UA wrapped into their analytics.
If you are setting up a new website Google will, as usual, attempt to force you to implement GA4 because they do love getting people to test their stuff for free! However, you will find that you can select an option that will give you a standards UA- analytics code.
If you have a Google Analytics code running already on your website then in GA you can go and upgrade your tag to GA4, this will not replace your existing tracking but simply create a new property that will be used to capture GA4 data. You will see this second property does not have the prefix of UA, and that is because new GA4 properties don't have this tag.
I've not actually been using the External keys for GA in SquareSpace (SS), but I just learnt about them. My preference is to simply use Google Tag Manager and then use the code-injection option to load across all pages (my question: any performance improvements loading Universal Analytics (UA) google tag via the external keys?)
I'm no guru but the learned advice for GA4 is to run it in parallel with your existing UA implementation to see how the data comes in. Also, if you have been doing any Event Tracking for UA via GTM then there is a complete rewrite process for mapping those events using the new GTM event for GA4. I will slowly crawl my way through that.
This is all driven by the fact that Privacy implementations are severely limiting the capacity of Google to measure effectively their paid campaigns (read: less value and less advertisers investing) and just as Facebook has recently done a deal with Shoppify to send conversion data back to Facebook without a pixel implementation, I expect GA4 addresses to some degree that, or at least paves the road for that outcome. For sure it is much easier to track conversions and also it is supposed to pull together much more efficiently cross device and cross app usage. I'll admit though the first time I went and saw the GA4 dashboard I was not amused!!
Hopefully this answers some questions.
GlynMusica
