> I've just had the slightly disturbing realisation that C++ streams are also monads
You might like [1].
It's part of Bartosz Milewski's extensive discussion of C++[2], but I'm unsure how that mass can be accessibly approached... maybe by starting around 2011. I very fuzzily recall liking his "Re-discovering Monads in C+" (2014)[3], but I didn't quickly find video. Apparently he gave a "Monads for C++" talk in 2017[4].