What difficulties have you encountered working with TypeScript?

The need to configure tsconfig.json and understand its options for correct compilation and typing. The difficulty of working with external libraries that lack typings (type definition files), and the necessity of searching for or creating @types packages. The problem of maintaining type safety when refactoring large JavaScript codebases, requiring gradual adoption of types. Sometimes excessive strictness of the type system, requiring the use of any or type assertions (as), which can reduce safety. Training the team in TypeScript syntax and concepts, especially when transitioning from JavaScript.