I don't think simply having the same types is a great reason to use TS on the backend given that many teams end up generating OpenAPI bindings in any case because the front-end models are typically a subset of the backend models (it is probably an anti-pattern to share your Prisma models with your FE).
That’s true, and Pick<BackendModel, …> works extremely well for me.
Setting up GraphQL or OpenAPI or any other code generation is way too arduous compared to just using TypeScript (also allows sharing logic).
> (Setting up OpenAPI)...is way too arduous
Even with Node frameworks like Nest.js, it is quite simple[0].
Beyond front-end use cases, the OpenAPI spec is pretty much required anyways if you are building a real API since tools like Redocly and other API documentation tools use the OpenAPI spec to generate your docs. Infrastructure like AWS API Gateway also consumes OpenAPI[1]; it seems to me quite handy to use the OpenAPI schema then as the source for client-side DTOs.
[0] https://docs.nestjs.com/openapi/introduction
[1] https://docs.aws.amazon.com/apigateway/latest/developerguide...