I agree the door could stand out, even though it does look nice as it is, it seems a little 'safe'.
anyhoo, I don't believe dark green or black would go with anything you have going on on your exterior as it is. I would recommend a rich wood finish whether it's a paint treatment or replacement. That would, at least, tie in with your roof and porch. Or pull one of the tones from either of those and bring it onto the door.
You could take a couple of pieces (or use both sides) of cheap plywood and paint with all of your color options, prop it in front of the door before leaving your house to go someplace and see how it looks when you return. OR prop the pieces and take pics like the one you posted and compare them.
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