There’s an updated (April 2022) Microsoft Azure Customer Solution VL Brief. This is a useful document detailing the rules for ISVs when creating customer solutions built on Azure: essentially, ISVs should purchase the Azure services through an EA or (and this is the addition to this new document version) direct from Microsoft via the Microsoft Customer Agreement. Partners intending to just resell the Azure services should use the Cloud Solution Provider (CSP) program.
Find this updated document here: https://bit.ly/39sdBgW.