I'm new to GIS and I'm using QGIS 3.4.5. I've been downloading individual SRTM tiles containing DEM data and merging them together in order to see the elevation of every point in a given area (such as the entire USA). It's slow and tedious to download all these files individually. Is there some XYZ tile server or other service I can connect to that will serve the DEM data for wherever my GIS canvas is located? Just like how I can add a Google Maps layer or a hillshade layer.