It might sound weirdly low for someone in IT in the USA, but first, not everyone commands FAANG sales, and second, wages in the EU are comparatively low. With some seniority, you can rise to $100k relatively easily, but you have to sell your soul to either some consulting company or old Fortune-500 industries.

So could be the dev takes an above-avg wage which would be around junior to semi experienced level developer and just does what they want to do: build a chess community.

EDIT: I don't fully understand the tax part, but if the nonprofit also pays his taxes and he goes out with $54k net, he's doing very, very well for an EU country. I've just reached that level give or take and I have lots of seniority in a really profitable old economy country. If I would be gunning higher, I'd have to do consulting or go the people management track.

[1] https://en.wikipedia.org/wiki/List_of_European_countries_by_...