Xml transformer architecture

I am a class to transform xml data based on specifications. There are multiple different input formats and corresponding sets of specifications. These specifications can often be grouped and have a natural hierarchical structure.

I want to make it so you can add custom functionality easily, and make it so the base transformation class simply applies that functionality. Luckily, I can use the same parameters for all of the functionality.

I have come up with the design below, but I feel like there is probably some way to improve it, or just a completely different design to use. I would appreciate any feedback, thanks!

abstract class baseTransformer
{ 
    int x = 10;
    XmlDocument inputDocument;
    XmlDocument outputDocument;
    public delegate void CustomFunction(baseTransformer obj);
    protected Dictionary<string, CustomFunction> delegates;
    protected void transform()
    {
        //read in what delegates to use from JSON

        //apply delegates
    }

    protected abstract void doTransform();
}

class derivedTransformer : baseTransformer
{
    protected int y = 20; //instance variables might be needed
    
    public derivedTransformer()
    {
        delegates.Add("myFunc", new CustomFunction(MyFuntionality));
    }

    protected void MyFuntionality(baseTransformer obj)
    {
        derivedTransformer myObj = (derivedTransformer)obj;
        //do stuff
    }

    protected override void doTransform()
    {
        //do some other stuff and then call transform
        transform();
    }
    
}