BuddyPress.org

/**

* bp_get_options_avatar()

* TEMPLATE TAG

*

* Gets the avatar for the current sub nav (eg friends avatar or group avatar).

* Does not check if there is one – so always use if ( bp_has_options_avatar() )

*

* @package BuddyPress Core

* @global $bp The global BuddyPress settings variable created in bp_core_setup_globals()

*/

What you want is:

<?= bp_core_get_avatar( $user->user_id, 2, 75, 75 ) ?>