What could be the disadvantages of using SINGLETON to implement SERVICE (service) according to the principle of Domain Driven Design?

Question

Design patterns

I am not a very experienced developer.
SERVICE is stateless in DDD. And it seems that you can use Singleton to implement it. But what can be the disadvantages of expanding the project. Whether in this case dependency of objects or complexity of testing can amplify.
In general, is it worth using a Singleton for a service in DDD?

Answer 1

What is so bad about singletons?
Use a DI container.