Generating a local backup of an AWS volume or snapshot
The edition of the backup you need is where you're going to be running it from, so Linux in this case, since presumably you can install the agent on the Linux EC2 instance and run the backups directly to S3 storage. It doesn't matter where you're copying the backups or what tool you're using to facilitate that data migration as there is no backup product involved in that process. You may want to scour the internet for an Amazon S3 file sync utility That can synchronize local disk with your S3 storage to avoid copying objects locally more than once.
Also keep in mind that you might be fine just keeping your data in S3. If you don't really need it locally you can save yourself the hassle of that process and the costs involved. Well we generally advocate for 321 backups, with a local backup and one offside in the cloud, that's generally for on-prem desktops and servers as opposed to servers that are already in the cloud. It certainly is more protection having a local copy, but there are costs involved in that process.
Let me also add, and I apologize for not mentioning this earlier, that you don't have to back up to S3. You could create an account with a company that offers lower cost storage like Wasabi or backblaze B2 and back up there for 5 to $6 per terabyte per month. The backups will likely run more slowly because the data needs to move out of the AWS environment and region into a different cloud storage vendor, but if the costs work better for you it may be a good option. Plus with some services like Wasabi there are no data egress fees, so should you decide to move the data locally from Wasabi You could do that at no charge.