In the past I spent a significant amount of time working on large C# projects with many files. The C# language can be verbose and require excess time to create new classes—particularly several years ago.
One newer feature in C# that I feel can make developing large, multi-file programs easier is the "global using" directive. While "using" as a directive only applies to the current file, "global using" applies globally to all files in the project.
So each file that you create—like a new class file—you can omit the commonly-needed using directives. In many projects, a single directive is used in many places—like the System namespace for programs that write to the console, or System.Text for programs that use StringBuilder. I feel global using directives are a valuable time-saving (and file-size-saving) feature in this language.