Only allow original uploaded image and Remove all image sizes generated by WordPress.

wp-remove-all-image-sizes.php

/*Remove all image sizes*/
function prefix_remove_image_sizes( $sizes ) {
	return array();
}
add_action( 'intermediate_image_sizes_advanced', 'prefix_remove_image_sizes' );


/*Removed scaled image size (-scaled as suffix on image name)*/
add_filter( 'big_image_size_threshold', '__return_false' );

/*Removed rotated image size (-rotated as suffix on image name)*/
add_filter( 'wp_image_maybe_exif_rotate', '__return_false' );