Your image’s src is pointing to the full size image, so it’s not an issue of permalink. The issue happens because of the sizes
values. There is a variable that determines the width of your content, which then later WordPress uses to generates the responsive sizes for your images.
This global variable can be set manually in your theme’s functions.php
file:
if( !isset($content_width) ) {
$content_width = 1920;
}
You can tweak with this variable to achieve your desired result.