If no claim of compatibility with other backends is provided I would be skeptical that it will be trivial by necessity.

I'm not that familiar with either technology, but as an example, deno kv claims strong consistency as the default; while dynamodb requires you to explicitly ask for strong consistency in queries and does not support strongly consistent reads on secondary indexes.

When not in deploy, you'd be stuck with a non distributed SQLite database for each instance your application is hosted on. There currently isn't a way to swap the backend for the deno kv API, so you would still need to update your code to use the new kv store that would have a different API. If you use redis instead, you'd be able to easily be able to switch providers by changing configuration options instead of having to update your code wherever it is used.