gistfile1.cs

public class DomainClass
{
    public DomainClass(AnotherDomainClass dep, string arg){
        //logic
    }   
}

public class AnotherDomainClass{
    public AnotherDomainClass(string arg, string arg2){
        //ctor logic
    }
}

// Builders
public class DomainClassBuilder
{
    string _arg;
    public DomainClass(string arg = "Good default value"){
        _arg = arg;
    }
    
    public DomainClassBuilder WithAnother(AnotherDomainClass anotherDomainClass){
        _anotherDomainClass = anotherDomainClass;
    }
    
    public DomainClassBuilder WithAnother(AnotherDomainClassBuilder anotherDomainClass){
        _anotherDomainClass = anotherDomainClass.Build();
    }
    
    public DomainClass Build(){
        return new DomainClass(_anotherDomainClass ?? new AnotherDomainClassBuilder("Some default"), _arg);
    }
}

public class AnotherDomainClassBuilder{
    string _arg1;
    string _arg2;'
    public AnotherDomainClassBuilder(string arg1 = "Good default", string arg2 = "Another good default") {
        _arg1 = arg1;
        _arg2 = arg2
    }
    
    public AnotherDomainClassBuilder Build(){
        return new AnotherDomainClassBuilder(_arg1, _arg2);
    }
}