Show current user posts in custom post type query

There are 2 fundamental problems here:

Problem 1

pre_get_posts lets you modify a query before it happens, and in this case you’re modifying the main query before it happens.

But you do this:

if ( get_post_type() == 'saved-orders' ) {

get_post_type shouldn’t work here as it’s too early, the main query hasn’t happened yet. Instead, lets ask the query object:

if ( 'saved-orders' === query->get( 'post_type' ) {

Problem 2

This is a syntax error, and not valid PHP:

$query->set( 'author' => $current_user->ID );

=> is only used in 2 situations:

array(
    'key' => 'value'
)

and

for ( $array as $key => $value )

Neither of which are function calls. The correct way to call the set method is:

$query->set( 'queryvar', $new_value );

With some beginner level PHP knowledge you should now be able to fix your filter.