@White Falcon I rechecked on it and yes like you said the height it also fixed to 460px. For this you will have to edit the code.
Go to the theme folder and open this file functions.php. Look for the following lines of code
add_image_size( 'slider-narrow', 1038, 460, true ); // used on Featured Slider on Homepage Header for narrow layout
add_image_size( 'slider-wide', 1400, 460, true ); // used on Featured Slider on Homepage Header for wide layout
You can make changes there. After changing the file size you will have to regenerate the images with the new sizes. You can regenerate the images with this plugin.
Also, I suggest you to make a child theme to make these changes so that you won’t lose the changes when you update the theme. You may also need to hire a developer on this one.