I guess it's a mixed answer, here there often aren't the smaller roads like D roads in France vs the more busy N roads. I've only biked a bit in Spain, in the Basque area for a few days, and my memories of the small roads that we were on we were just like the quiet D roads in France.
clearly though from your photos, you are taking the time to find and go on smaller roads, which like I often comment on, look like fantastic fun to ride on.. For sure it takes more planning time, and using Google maps and satellite views to research, and people do that here too, but my feeling is that in Europe there are just more networks of smaller roads than here.
at least with the internet and GPS stuff, it's a lot easier to find and share really interesting routes avoiding busier roads.
yes, when riding here in EU don't use the N roads = National Roads, too much traffic.