Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - Help/Tips/Tricks how to put splitscreen of player 2 on 2nd monitor?

is it possible to put splitscreen of different players on different monitors?

Not natively. If the second monitor is extending the desktop, you can switch the game to windowed display mode, and span it across the monitors.
The force split screen setting doesn't apply during combat, but the player who does not have their turn can open the in-game menu (or their inventory, etc) to split the screen.