Question on Various Topo Maps

I just upgraded from Fenix 5X Sapphire to 7X Solar Sapphire and just loving the display, features and responsiveness. 

I use my watch for sports and hiking/scrambling and I rely on it heavily in the mountains.  I noticed that Fenix 7 now contains Topoactive Maps for North America, my 5X included Topo Canada.  I previously used talkytoaster maps for Canada on my 5X which are also based OSM.

It seems the Topoactive maps have a DEM based on 30m contours while the other maps had data for 10m contours but except for a Garmin Australian site I can't find any technical info on the various Garmin Topo Maps.

Can someone point me in the write direction for Garmin Map specs so I can verify the DEM.  Does anyone know of any sources of more accurate DEM that I can load on top of say TopoActive to get better resolution of relief in mountainous areas and also to have a better calculation of my elevation using GPS+DEM data?

Thanks in advance