Encryption or vSAN is not my strength. The KMS has to be KMIP compatible if we want to encrypt vSAN.Can we use Azure Key Vault for vSAN encryption?
, No, that is not on the VCG so not supported:
https://www.vmware.com/resources/compatibility/search.php?deviceCategory=kms&details=1&keyword=Azure&page=1&display_interval=10&sortColumn=Partner&sortOrder=Asc