My former student association, BEST, ran on https://best.eu.org https://best.eu.org for over two decades. They also have best-eu.org as a mitigation strategy (t

My former student association, BEST, ran on https://best.eu.org https://best.eu.org for over two decades. They also have best-eu.org as a mitigation strategy (they unfortunately didn't manage to grab best.eu back when .eu launched). IIRC the eu.org was always reliable so it's not been a problem. They do a lot of nontrivial IT, with all kinds of internal sites of varying quality, tons of email lists on a homecoded engine, and so on, and so forth. While I was involved (over a decade ago, mind), the domain was never a source for trouble. I think you could do worse for a free subdomain provider.