It’s $250/month for a c6g 2xl 1tb ebs on demand pricing go reserved instances. Given they use AWS and are a major customer, you can expect excellent pricing above the above public pricing quote.
Considering the cost of a developers time, and you can do shenanigans to drive that even lower, this all feels totally reasonable.
If you truly need that kind of perf (and at Amazon, we had plenty of dev desktops running on ebs without that kind of performance) then you should really opt for an instance type with local storage.
Ive been deep in to implementing macOS CI workers on AWS where that isn't an option (or rather, it is an option, but it is unsupported and Amazon only buys Macs with the smallest possible SSD for the given configuration). So your options are to pay an arm and a leg for fast EBS, or pay an arm and a leg for a pro or max instance with larger internal SSD.
Considering the cost of a developers time, and you can do shenanigans to drive that even lower, this all feels totally reasonable.