This is a reason why so many enterprises use C#. Most of the time you just use Microsoft made libraries and rarely brings in 3rd party.
Or purchase third party libraries. This does two things - limits what you drag in and also if you drag it in you can sue someone for errors.
Having worked on four different enterprise grade C# codebases, they most certainly have plenty of 3rd party dependencies. It would absolutely be the exception to not have 3rd party dependencies.