I'm not clear on if this is supposed to be disagreement or elaboration or education.

The fact that in a language like Haskell, you can perform something like async-await with futures (which are absolutely a kind of monad) in a natural way is precisely what I had in mind with what you quoted.

Regardless, the specific heritage of async-await syntax seems rooted in procedural languages (that do borrow much else as well from functional languages, yet are still not functional in any meaningful sense) like C# and python. They are absolutely an attempt to bring some of the power of something like monadic application (including do notation) into a procedural environment as an alternative to threads (green or otherwise), which hide the execution state machine completely.