Custom arguments in author page loop / query

I have a post meta field in which a secondary author is registered (key=sec_author_name). On the author page (website/author/name) I’d like to show posts from this author or post where this author is the secondary author.

To do this efficient I use the pre_get_posts action.
First I use unset to remove the current filter on author_name: unset( $query->query_vars[‘author_name’] );

And then I’d thought to do something with meta_query, but I can’t figure it out.

I currently have this:

if ( $query->is_author() && $query->is_main_query()) {
	unset( $query->query_vars['author_name'] ); 
	$query->set( 'meta_query', array(
		'relation' => 'OR',
		array(
			'key'     => 'sec_author_name',
			'value'   => 'jorim',
			'compare' => '='
		),
		array(
			'key'     => 'author_name',
			'value'   => 'jorim',
			'compare' => '='
		),
	) );
}

And this gives me a 404 ??

It’s probably because I try to compare a meta field with a non meta field with meta_query… Is this possible this way?

If not, I don’t mind adding a custom piece of query to the query to retrieve the right post ID’s..

Thank in advance!
Jorim