I'd actually argue against (at least Western and Northern) Europe for digital nomads, purely because you could move to somewhere in the developing world and live an incredibly comfortable lifestyle thanks to a much lower cost of living. Your mileage will vary based on what languages you speak, of course.
Living in the developing world brings its own kind of issues, medical emergencies for instance, as well as the English proficiency around you (which is probably one of the reasons the top 3 countries are DK, DE and NL)
Probably region dependent, but the cliche seems to be that when asked, Germans say "they don't speak English very well", while actually having a quite good level (based on what visiting English speakers say, anyway)
No, it is/was meme on the other site, in a lot of statistics Portugal aligns more with Eastern Europe. If you go far enough to the east you end up in the west, so Portugal is just a far eastern european country instead of western european.