These are not the same thing.
Contentment is being satisfied in God and his provision and portion at a given time.
Complacency is being satisfied in myself and apathetic toward the future.
I frequently confuse these, and assume complacency is contentment, or that desire for movement is discontentment. That is, I tend to do nothing and think I’m spiritual. Or I tend to want bigger and better things (like to be a pastor or, in past times, a husband) and assume that I despise God’s goodness.
Surely, there is a time for everything under heaven. A time to be single, and a time to serve coffee.
But it is not wrong, automatically, to want to be a husband and to be a pastor. In fact, both are good: “He who finds a wife finds a good thing and obtains favor from the LORD” (from Solomon) — and — “This is a faithful saying: If a man desires the position of an elder/pastor, he desires a good work” (from Paul). And both are from the Lord, the good Father who delights to give good gifts to his children and his church.