It takes some patience. I‘ve just finished setting up my triple-mon using three identical 43” 4K TVs. The key to get them all aligned, I’d recommend two things:
First, watch the YT video(s) by Russ Barlow. It shows you the mechanics behind multi-view. MSFS Surround Vs. New Multiview: The Best Sim Solution - YouTube
Second, use this invaluable alignment tools to help make your fine adjustments. Triple Screen Calibration Utility » Microsoft Flight Simulator
After two or three hours of trial and error, it runs just about perfect. Surprisingly, the same settings work from a small aircraft to an airliner—that’s better than X-Plane.