A nation not yet mentioned here, a bit lesser known, but a great contender is Burgundy into Lotharingia.
It has a killer idea set + mission tree (extra missionary, -25% CCR, 5% permanent admin efficiency from mission tree, fairly easy to get).
It's also in the best trade node in the game, and is close to England so it can stop England early and easy. Because of the huge amount of money, you can also easily spread out across the world using money along (charter trade company). At dip tech 10 you can charter in Morocco and then West Africa, the latter is easy to conquer and trade can be funneled toward the English Channel. Using said money you can spread out conquest easily.
It has a killer idea set + mission tree (extra missionary, -25% CCR, 5% permanent admin efficiency from mission tree, fairly easy to get).
It's also in the best trade node in the game, and is close to England so it can stop England early and easy. Because of the huge amount of money, you can also easily spread out across the world using money along (charter trade company). At dip tech 10 you can charter in Morocco and then West Africa, the latter is easy to conquer and trade can be funneled toward the English Channel. Using said money you can spread out conquest easily.