Is there a limit to the download speed/bandwidth when restoring a backup?

Now granted, I'm trying to restore a single ~300-400GB EDB.

But this is on an EC2 instance with over 1Gbps down for bandwidth. The storage restoring from is Wasabi. They have a "speed test" feature to specifically gauge bandwidth to/from them, from the machine your backing up/restoring too. That's looks good.

Yet, I'm averaging only ~40Mbps download when trying to restore.

Adjusting thread count doesn't seem to make a difference, and at face value it looks like "chunk size" is only relative to upload.

Any thoughts or insights?