How can I create a dynamic graph extension

I found no way to do it so I had to iterate all extension and check for the one I need, example:
 

        private MyExtension<TGraph, TPrimary> GetTeamsGenericGraphExtension()
        {
            PXGraph graph = Base.TypelessClone();
            PXGraphExtension graphExt = null;
            MyExtension<TGraph, TPrimary> graphGenericExt = null;
            int i = 0;

            do
            {
                graphExt = graph.GetExtension(i++);
                graphGenericExt = graphExt as MyExtension<TGraph, TPrimary>;
            } while (graphExt != null && graphGenericExt == null);

            return graphGenericExt;
        }

CLARIFICATION

for example let say I am getting a graph ext like this

APInvoiceEntry_ApprovalWorkflow BaseAW = Base.GetExtension<APInvoiceEntry_ApprovalWorkflow>();

Now instead of “APInvoiceEntry_ApprovalWorkflow” I want dynamically replace the base graph part like this 

var graphExtensionName = $"{typeof(TGraph).Name}_ApprovalWorkflow";

how can I do this?