Limitation of 6MB file attachment while uploading (through API Gateway) to object storage?

I have a requirement to develop the cloud function to perform CRUD operations on file attachments into Object Storage. But I noticed the 6MB limitation of attachment content while uploading via Gateway.
Ref: https://docs.oracle.com/en-us/iaas/Content/APIGateway/Reference/apigatewaylimits.htm
i.e, client request -> API Gateway -> attachment function -> object storage

How to overcome this issue?
Since sometimes I need to upload large files and hence I found the multipart support and it works well from the cloud function here, but not sure how to receive/interpret the multipart/form-data body request in the cloud function.

Also, I referred to the sample codes and didn't get anywhere on how to receive the body content in the form of a multipart (in the handler class) while sending a request through API Gateway. Is there any specific example available for this use case?

Start with the linked API Gateway limits and Object Storage multipart-upload documentation, then inspect the repository for any cloud-function or multipart request examples. Done means providing a specific, documented way to receive multipart/form-data through API Gateway for the described upload flow.