Auto alignment of device template will work should work for API based Discovery as it get the sysoid information. Right now it is limited only SNMP based disovery.
@thangaselvi - NCM picks up the default template based on device type and from what I understand when you use API based discovery for SDWAN thats not the case as device type is not recognised by NPM. Based on the same this feature request makes sense - thanks for raising it.