Add a custom settings tab to the user account page in BuddyBoss. Place code in theme child's functions.php file

add_custom_settings_tab.php

<?php
function my_custom_user_settings_tab() {
    // create the Custom Tab in the settings navigation
    bp_core_new_subnav_item(
        array(
            'name' => __( 'Custom Tab', 'buddyboss-theme' ), // Replace 'Custom Tab' with the name of your tab
            'slug' => 'custom-tab', // Change this to your desired slug
            'parent_url' => bp_loggedin_user_domain() . 'settings/',
            'parent_slug' => 'settings',
            'screen_function' => 'add_custom_user_settings_tab',
            'position' => 80, // Adjust the position as needed
            'user_has_access' => bp_is_my_profile(),
        )
    );
}
add_action( 'bp_setup_nav', 'my_custom_user_settings_tab' );

function add_custom_user_settings_tab() {
    // Loads the Custom Tab content
    add_action( 'bp_template_content', 'my_custom_tab_content' );
    bp_core_load_template( 'members/single/plugins' );
}

function my_custom_tab_content() {
    // Include the Custom Tab content template file or shortcode
    // Replace this line with the appropriate code to include your content
    // For example, if using a shortcode: echo do_shortcode( '[your_custom_shortcode]' );
    include_once WP_CONTENT_DIR . '/path/to/your/custom-tab-content.php';
}
?>

To set the icon use CSS, for example:

.subnav #mytab-personal-li #mytab::before { content: "\\eef8"; }

Where #mytab-personal-li is the ID of the list item of the new tab and #mytab is the ID of the <a> tag. Select the icon from the BuddyBoss Font Cheatsheet. (The extra "\" is to ensure that it will not be ignored as an escape character).