Hi Rojo,
Welcome to the BuddyDev Forums.

I am sorry that we could not get back to you over mail. Things have been a little bit hectic here as we are trying to improve the support experience.

Now getting back to the topic, which version of BuddyBlog you are using? Is it version 1.1 or above? If yes, most of the things you want can be configured from Admin settings.

Please visit Dashboard->settings and click on the ‘BuddyBlog’ menu. You will see the settings option there.

1. Please check the settings for ‘Show single posts on user profile?’ make sure it is set to yes. That will make the posts to be linked on profile. They will be still visible on the blog archive post(on main site, I will get back on excluding in a minute.

2. To exclude the posts from the main blog:- There are multiple ways to achieve it. I am not sure which will suit you the best, so I will list both the approach.

2a) If possible, you can create a custom post type and select that as the BuddyBlog post type from the settings page. This will make sure that the custom post type is never visible on your main blog.

2b) Second approach is to limit posts to 1 category and exclude that category from main blog.

It will need some code

add_action( 'bsfep_post_saved', 'buddydev_add_default_category_to_post' );
function buddydev_add_default_category_to_post( $post_id ) {
	
	$post = get_post( $post_id );
	
	
	if( ! $post )
		return ;
	if( $post->post_status == 'publish' ) {
	
		$term = 'alpha-beta';//change this to your category slug

		wp_set_object_terms( $post->ID, $term, 'category');
	}
}

Please change ‘alpha-beta’ to your category slug in the above. Make sure you have Enable taxonomy disabled in the settings. Now when the user will post, It will be assigned the given category.

Excluding category

function buddyblog_custom_exclude_category( $query ) {
	//don't modify in admin list or on BuddyPress pages
	if( is_admin() || is_buddypress() )
		return ;
	
    if ($query->is_main_query() ) {
        $query->set( 'cat', '-32' );//IMPORTANT: change 32 to your category id. Please make sure to keep the minus(-)
    }
	
}
add_action( 'pre_get_posts', 'buddyblog_custom_exclude_category' );

Make sure to change 32 to the user category id.

I will prefer the first approach though as that is very straightforward

3. Change slug ‘buddyblog’ from url

define( 'BP_BUDDYBLOG_SLUG', 'some-slug-that-you-want');

Put that code in the bp-custom.php( link: https://buddydev.com/docs/guides/guides/buddypress-guides/what-is-bp-custom-php/) and that should do it.

Let me know if you need further assistance.

Thank you
Brajesh