> The thing that would put me off using DynamoDB is the same reason I wouldn't use any other tech - can I download it?

Amazon provides a downloadable version for development. I don't know how close it is to the real thing, but it makes it easier to do local dev.

Localstack also supports it in their paid version

The downloadable version is nowhere near ready for production. It's performance is also excruciatingly slow.

It doesn't really make any sense to use it locally - the whole point is that it's managed. If you just want a clustered key value store you could use Cassandra, Garnet, etc.

I think people mostly use it for unit testing functionality since it’s generally a faster dev loop compared to running integration tests.

It's not supposed to be used for production, it's supposed to be used for development