In theory, yes. You could create a Widget Blueprint with a Definitive Painter instance, retrieve the rendered texture and set is as a parameter of a dynamic material.
You should keep the number of DP instances at minimum. For that, DP supports Templates. For example, a DP Template can contain a button that can be reused multiple times. Another DP instance would be a whole UI with multiple Templates within. All child Templates automatically merge into their parent to save some performance.