For a long time, 34-inches was the largest screen size you could get for an ultrawide monitor, but in 2023 there are now plenty of screens that are much larger - and therefore more immersive. Our number one pick for the best ultrawide monitor is the LG UltraGear 38GN950, which is 38-inches.
Meanwhile, the Samsung Odyssey Neo G9 is a massive 49-inches, with a resolution of 5,120 x 1,440. If you want the largest ultrawide monitor in 2023, then the Samsung Odyssey Neo G95C is the one to get - it offers a huge 57-inches of screen. You'll need a lot of desk space, though.