> There is a component in contentment that I think is lacking in complacency...that of general happiness.

I don't see it that way, complacency can be just contentment from one's own perspective — it may take a third party to call it complacency (sometimes wrongly so, such as that parable[0]).

[0] https://thestorytellers.com/the-businessman-and-the-fisherma...

(Though that parable fails to account for unforeseen financial emergencies and such...)