> It's also a bummer that you need the containers package for basic DS. So, batteries not included

Batteries are included, because containers ships with every distribution of GHC, and you don't need to use stack or cabal to expose it:

    % ghci
    GHCi, version 9.4.8: https://www.haskell.org/ghc/  :? for help
    ghci> import Data.Map
    ghci> singleton 5 "Hello"
    fromList [(5,"Hello")]

Please try the same at your end and if it doesn't work for you then you can let me know and I'll try to help you resolve the issue.