12TB is $960/month in gp3 storage alone. You can buy 12TB of NVMe storage for less than $960, and it will be orders of magnitude faster than AWS.
Your use case is the _worst_ use case for the cloud.
Your use case is the _worst_ use case for the cloud.
For some reason people more easily understand the limits of CPU and memory, but overlook disk constantly.
I/O is hard to benchmark so it's often ignored since you can just scale up your disks. It's a common gotcha in the cloud. It's not a show stopper, but it blows up the savings you might be expecting.
Also, SAN is often faster then local disk if you have a local SAN.