Hmm when I try that (both), the sub-pages don’t even show up under the custom post types:
// Financial Reports Archive Options
acf_add_options_sub_page( array(
'title' => 'Financial Archive Content',
'parent' => 'edit.php?post_type=tgf-financials',
'capability' => 'manage_options'
) );
// Grants Archive Options
acf_add_options_sub_page( array(
'title' => 'Grants Archive Content',
'parent' => 'edit.php?post_type=tgf-grants',
'capability' => 'manage_options'
) );