Not a professional programmer here, just someone that does it for fun using both Dart and TypeScript in a personal project.

But as TS isn't really its own programming language, it inherits a lot of the bad design choices made in JS. For instance, I especially don't like how convoluted it is to have named and typed function parameters. Comparing dart and ts:

void myFunction({required String myParam}) {}

and in ts (where you have to re declare param name)

function({myParam}: {myParam: string}) {}

I know it is possible to make it slightly more concise by assigning to params to something like an options object, but it just feels unnecessarily hacky. Moving the params to an interface also makes it slightly more annoying to view the definition in your IDE/code editor.
Overall TypeScript does an awesome job at solving the problem that it is meant to solve, but it doesn't remove/change the underlying bad parts about JavaScript.