Hi Jem,
Thank you for asking. Since you are using the code from the linked topic, It is easy.

In that thread, I had stored the gallery_id in a meta like this

update_user_meta( $user_id, '_mpp_predefined_gallery_photo_1', $gallery_id ); //you can change the key to anything

So, All we need to do here is reuse this gallery id like this

<?php if ( bp_is_my_profile() ) :
	$gallery_id = get_user_meta( bp_loggedin_user_id(), '_mpp_predefined_gallery_photo_1', 'true' );//please change the key to the one you re using
	?>
<?php echo do_shortcode("[mpp-uploader gallery_id=". $gallery_id ." ]");?>
	
<?php endif;?>

Please make sure to use the correct key that you had stored in the usermeta.

Please do let me know if that works fro you or not?

Thank you
Brajesh