It's almost impossible to get a permanent citizenship in any of the scandinavian countries (besides Svalbard, which is a part of Norway, but really strange case). You either have to be some sort of highly educated person or marry someone with a permanent citizenship, and even then there are some restrictions.
Inside of EU and Schengen you should be able to get a limited work permit. Then you are usually covered by local health care after a couple of months paying tax.
That seems like a pretty low bar for "almost impossible", as I would expect most HN readers are both 1) highly educated and 2) single, and so the two avenues you mention are amongst the most accessible to them.
There are far more difficult places to gain citizenship (e.g. Liechtenstein, China).
Inside of EU and Schengen you should be able to get a limited work permit. Then you are usually covered by local health care after a couple of months paying tax.