OOTB, Assets/pages can be published from AEM author to publisher instance. In order to publish the AEM assets to an external cloud space, you will need to develop a custom solution (API/Java based development).
Please check below document which has information on connectors and understand possibilities or limitations.
https://experienceleague.adobe.com/docs/experience-manager-64/administering/integration/sharepoint-c...
Hope this will helps you.