Even I have the impression that the bp-custom.php do not run!
I have tried several codes inside the file Placed in /wp-content/plugins/.
for example I try to set the landing page for the users to Profile: define( 'BP_DEFAULT_COMPONENT', 'profile' );
or Change the default tab opened when looking at a group to forum define( 'BP_GROUPS_DEFAULT_EXTENSION', 'forum' ); https://codex.buddypress.org/getting-started/customizing/changing-internal-configuration-settings/
… Nothing happens!
I am realy newbee with that stuff! damm….