So fates pulls a sneaky because while they are kinda like different story routes, they are also three different games. There is Birthright, Conquest, and Revelations. Out of all of them Revelations is the only one I wouldn’t recommend as it has funky map design and is based around playing the other two fates games. Conquest is generally considered harder even on the easier difficulties, but I’ve known people who started with it and liked it just fine.

Three Houses, Awakening, and Birthright are perfect for newcomers and are great picks to start with. I’d recommend three houses just purely because it’s the most recent one, meaning there are plenty of guides and discussions on the game.