In the ethical nonmonogamy (ENM) circles, the form of polygamy is usually frowned as it is a form of power over others. However polyamory and other forms of non monogamy are much practiced and common.

So like gitit?

Yes, it has two mainstream libraries, simple-postgresql and hasql both of which have seen use in professional setting.

For server, you have choices such as servant, yesod and scotty, which too have seen industrial use.

I don’t think it’s possible to give an universal answer for that. Can you do it with Haskell? You bet. Can you do it with Rust? Sure thing.

There are plenty of other considerations, such as are you doing it by yourself, are you hoping for a community, for work, how much effort are you willing to put etc.

I’ve been a nixos user for years, out of curiosity what was it you tried that was a PITA?