.NET can serve the same use cases as Java, it's not just for windows programming. It's actually getting really good.
NodeJS does nothing better than anyone. The only things I can think of that make node worth using is electron and react native, maybe Next but I'd much rather do SSR in a real programming language personally. I would never use node as a pure backend, there's just no reason to and JS is an F tier language. TS brings it up to like C but it's still just not good enough to compete.
I can't see any reason to choose node for typical backend programming and such unless your devs only know JS. Any other language is probably better suited.