If anyone is interested in a Napoleonic wargame similar in scope and depth to Ultimate General, I highly recommend John Tiller's Napoleonic Campaigns. They are turn-based and bit old-school, but have many gameplay elements that should interest fans of Ultimate General - full-scale armies with detailed orders of battle, each org element with its own unique leader, ability to offload command of a division to AI (with specific objectives), a lite strategic campaign that gives purpose to battles etc. It is notoriously complex and cerebral, but that should not be an issue with Ultimate General players. They are almost exclusively covered by this youtuber, if you want to get a taste.
There is Scourge of War Waterloo as well. But Waterloo is to Napoleonic Wars = American Revolutionary War is to history of warfare - small, limited, unbalanced, lacking masterminds and masterpieces, forgone conclusion. And the developers have disbanded. So there will be no Scourge of War: Austerlitz, or Scourge of War: Eylau etc.