Hi @JanneWassberg and @tjthomsonjones, apologies for the late reply here. After doing some research and testing out Google Analytics and Google Tag Manager I was able to note that Ecommerce data is retrieved when just using Google Analytics. It does take a couple of hours but the transaction data shows up in Google Analytics.
I then proceeded with trying to capture conversions with the Google Tag Manager and Google Analytics and realized it is a fairly involved process that requires a data layer to be implemented into the site. This is standard for tracking Google Tag Manager conversions. Here is a video series I found on YouTube on how to track Ecommerce with the Google Tag Manager: Google Analytics Ecommerce Tracking with Google Tag Manager (Part 1) - YouTube
You can download the Tag Assistant from Google to verify your data layer information is correct as you are going through the video tutorial.
We also recently released a video tutorial in the Webflow University on working with the Google Tag Manager: Google Tag Manager — Webflow tutorial - YouTube
Hope this helps!