Brajesh, for some reason after updating BP none of this code in my child theme functions.php is working, the slug stays buddyblog and all cats + tax show:

define( 'BP_BUDDYBLOG_SLUG', 'battleblog');
function buddydev_add_default_category_to_post( $post_id ) {
    
	$tax = array_filter( $_POST['tax_input'] );
	
	if( empty( $tax ) && $post_id ) {
		//no category was set
		$term = 79;//ID
		wp_set_object_terms( $post_id, $term, 'category' );
		
	}
    }

function buddyblog_show_custom_cats( $settings ) {
	$tax = array();

	$tax['category'] = array(

		'taxonomy'  => 'category',
		'view_type' => 'dd',
		'child_of'  => 91, //CHANGE It with the correct ID,
		'orderby'   => 'slug',
		'order'     => 'ASC'
	);

	$tax['post_tag'] = array(

		'taxonomy'  => 'post_tag',
		'view_type' => 'dd',
		'include'   => array( 83,85,88,92),// tag ids.
		'orderby'   => 'slug',
		'order'     => 'ASC',
	);

	$settings['tax'] = $tax;

	return $settings;
}
add_filter( 'buddyblog_post_form_settings', 'buddyblog_show_custom_cats', 100 );
add_action( 'bsfep_post_saved', 'buddydev_add_default_category_to_post' );

I never had a bp-custom.php, I just used the child function file and it worked before. If that is why its not woorking now where in my child can i add that file?

could this be fixed with a custom registration template in the child theme?

no you are right they never had any sub tabs at all. I wonder if this is fixable by customizing the child theme

any luck with a little snippet?

Absolutely, and wherever you are happy Thanksgiving from america brother.