Recently I had setup a daily extraction automation from a marketing platform and they had SOAP API. I had worked with xml before, so after some trial and error I was able to fetch marketing data from trafficvance.com platform right inside Google Sheets
Nice post from Urwa Shabir highlighting how to interact with 3rd party APIs using SOAP which relies heavily on XML. The post covers formatting a SOAP request now that SOAPService is deprecated in Apps Script, as well as parsing the XML response.
Source: Marketing Data Extraction using SOAP API — Apps Script Automation
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.