Hey @VizSim, welcome back to the forum!
Great question, I think a good starting point is this Cesium for Unreal Tutorial on Editing Tileset Materials and this existing topic on the forum How to setup the transparency of RasterOverlayComponent, specifically Kevin’s client side solution. You should be able to achieve a result that blends Google Maps 2D Satellite and Google Maps 2D Roadmap.
Let us know how that goes!