If we consider migrating to AEMaaCS, how and what are the considerations/modifications for datastore/nodestore and how they will be migrated to AEMaaCS?
Ex: If i use a fileDataStore how it is migrated to AEMaaCS.
In addition to the details shared by Kunal, you can reference the below link for Content Transfer Tool which mentions the considerations for content transfer and 'File Data store' can be used with it.
AEM as a cloud service uses underlying cloud storage for blobs. The blob storage is shared between author and publish tiers. You don't have to do any datastore configurations in cloud as the underlying storage service is managed by Adobe. You just have to migrate the content from on prem AEM to cloud using the content transfer tool.
In addition to the details shared by Kunal, you can reference the below link for Content Transfer Tool which mentions the considerations for content transfer and 'File Data store' can be used with it.