I currently tolerate OpenAPI because I'm using a robust code-first approach (Tapir in Scala) on the server side, but I otherwise agree, the ecosystem seems brittle.
TypeSpec and Smithy live in a similar space here. You can generate OpenAPI specs from them, or you can generate assets directly from them. OpenAPI is one of the many possible outputs from TypeSpec.
This is an example the author created of TypeSpec being used to generate clients in many languages as well as the OpenAPI spec.
We've been looking to buy into Smithy heavily as we no longer have the appetite to deal with OpenAPI and it's horrendous ecosystem.