Question about background image sizes and custom positioning

I’m new to Elementor and trying to better understand how custom positioning (section > style > position/custom) works so I can avoid any potential issues with my static homepage layout, specifically the background (hero) image, being viewed on different screen sizes.

I replaced my theme demo’s full width background image (content width is boxed in Elementor) with another image that’s the same size as the original: 1600 x 800.

I then used custom position to move the focal point of the image -75 pixels (to the left).

Since I’m working on a 13 inch laptop, I can’t see how this move affects the position of the right edge of the image but from playing around with other images and positions I’ve noticed that some are repeated/cut off when I test them by flipping a phone to landscape orientation.

Which makes me wonder what my background “hero” image will look like on a 1920 x 1080 monitor, for example.

Am I right to expect it to be cut off or repeated (according to my Style settings)? If so, should I make my images extra wide to compensate?