Typescript is a really powerful language due to the fact that it is superset of JavaScript. It allows you to do things with types that you cant do in other strongly typed languages like Java or C#. Learning JavaScript first, you would have an easier time grasping advanced typescript concepts. But like others said, JavaScript does allow you to learn bad habits. It takes years to learn how to write JavaScript in a way where you won’t shoot yourself in the foot. TypeScript first would theoretically help keep you on a learning path that would mitigate picking up bad habits. But typescript is a superset of JavaScript after all. If one is determined to sidestep all the nice typings that TypeScript provides you, one can and you will lose all the benefits of TypeScript anyways.
It helps to get paid a lot to not think about that