The Snap (MCU) occurs during the American Civil War. How does this change history?

This follows the same prompt as the others: Spider-Man (MCU) gets his hands on a Sling Ring sometime before the Battle of Titan in Avengers: Infinity War. After he wins, Thanos goes to Wakanda, but is secretly followed by Spider-Man. After he witnesses Thanos insert the last infinity stone in his gauntlet, Spider-Man (MCU) uses his Sling Ring to send Thanos (MCU) to an alternate reality before he can Snap half of all life out of existence.

There’s just one problem: Thanos has been sent to September 17, 1862, during the Battle of Antietam during the American Civil War. Before he realizes what happened, Thanos snaps.

Half of the universe’s population of living organisms as of 1862 is now dead.

Strictly talking about humans, confirmed casualties include (but not limited to): 1. Abraham Lincoln & his entire administration (Lincoln’s family is spared) 2. John Wilkes Booth 3. Robert E. Lee 4. William T. Sherman 5. Ulysses S. Grant 6. Stonewall Jackson 7. Tsar Alexander II 8. Benito Juarez 9. Napoleon III 10. Maximilian I

How does this affect history?

Assumptions: 1. Thanos hasn’t left the MCU 2. Because there are no movies about the Civil War in the MCU, everything before Thanos’ appearance in the Battle of Antietam happens the same as our timeline.