On the one hand, I agree that writing unit tests before the design has settled and the interfaces are stable can be frustrating. Many people find TDD a chore because of this.
But if you delay adding unit tests until after the interfaces are more or less stable, it gives you higher confidence to refactor the implementation, which is invaluable.
On the other hand, the benefit of TDD is that it helps with the actual API design. You immediately experience the API as a user, and this process drives the implementation, and ensures you end up with a friendly and testable API. If you add tests after the design, then you might have a more difficult time refactoring the implementation to make it testable, and the DX could suffer.
So I see both sides of the argument, but in either case, unit tests are very important, and I wouldn't avoid them just because they're a chore to maintain.
TDD gives you a testable interface, but otherwise doesn't help think what the api should be.
You can so TDD using only integration tests. This means tests are not added after the design. It only means that your individual functions don't have tests. I do this allowed the time, it makes refactoring easier.
The most common objection: how do you know what failed? Turns out to be a non issues, since I make my tests fast I can run them often and thus the failure has an obvious cause: the last thing I changed.
But if you delay adding unit tests until after the interfaces are more or less stable, it gives you higher confidence to refactor the implementation, which is invaluable.
On the other hand, the benefit of TDD is that it helps with the actual API design. You immediately experience the API as a user, and this process drives the implementation, and ensures you end up with a friendly and testable API. If you add tests after the design, then you might have a more difficult time refactoring the implementation to make it testable, and the DX could suffer.
So I see both sides of the argument, but in either case, unit tests are very important, and I wouldn't avoid them just because they're a chore to maintain.