MongoDB is a cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schema, so the best to be migrated to Oracle NoSQL Database.
https://blogs.oracle.com/nosql/migrate-mongodb-data-to-oracle-nosql-database Autonomous transaction Processing Serverless (ATP-S) isn't supported yet for EBS database

Pre-authenticated requests provide a way to let users access a bucket or an object without having their own credentials, as long as the request creator has permission to access those objects.
For example, you can create a request that lets operations support user upload backups to a bucket without owning API keys. Or, you can create a request that lets a business partner update shared data in a bucket without owning API keys.
When creating a pre-authenticated request, you have the following options:
You can specify the name of a bucket that a pre-authenticated request user has write access to and can upload one or more objects to.
You can specify the name of an object that a pre-authenticated request user can read from, write to, or read from and write to.
Scope and Constraints
Understand the following scope and constraints regarding pre-authenticated requests:
Users can't list bucket contents.
You can create an unlimited number of pre-authenticated requests.
There is no time limit to the expiration date that you can set.
You can't edit a pre-authenticated request. If you want to change user access options in response to changing requirements, you must create a new pre-authenticated request.
The target and actions for a pre-authenticated request are based on the creator's permissions. The request is not, however, bound to the creator's account login credentials. If the creator's login credentials change, a pre-authenticated request is not affected.
You cannot delete a bucket that has a pre-authenticated request associated with that bucket or with an object in that bucket.

You can define the members of the dynamic group based on the following:
- compartment ID
- instance ID
- tag namespace and tag key
- tag namespace, tag key, and tag value
Supported variables are:
instance.compartment.id - the OCID of the compartment where the instance resides instance.id - the OCID of the instance tag.<tagnamespace>.<tagkey>.value - the tag namespace and tag key. For example, tag.department.operations.value .
tag.<tagnamespace>.<tagkey>.value='<tagvalue>' - the tag namespace, tag key, and tag value. For example, tag.department.operations.value='45'