For the OP - be careful with AWS, the closest pricing to one dollar per terabyte is S3 Glacier Deep Archive and you'd be surprised how expensive a full restore can be in the event that you need to do so in terms of restore pricing, egress cost, etc.
Another NAS isn't really a good solution (unless you can place it in a different house) - the goal of a cloud back up is that it's offsite.
Another NAS isn't really a good solution (unless you can place it in a different house) - the goal of a cloud back up is that it's offsite.