Replacing a background of an image can be a challenge. The trick is to find the right background that has similar colors, tones, lighting and looks like it belongs to the main image. Once you find the right image, cycle through the layer’s blend mode selector to see which mode blends best. This applies to any image editing software that uses layers, including Photoshop and Luminar.
Want to learn more? Check out this article, “Changing a Background with an Image Overlay in Luminar 2018”