Transfering a file from local machine to EC2 instance

1. What I have done in the past is upload the file to a S3 bucket.
2. Ensure the IAM role on the EC2 has access to the bucket
3. Use AWS S3 cli to copy the file locally to the EC2

Hello.

For Ubuntu, I think it is possible to use Systems Manager Session Manager.
How about connecting to EC2 with Session Manager and setting a private key for SCP?
https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager-prerequisites.html