Show name in place of Widget text (logged in)

its not possible yet .

I will consider adding it for future updates.

in case you are still looking for solution.

yes. First make sure you have version 2.5.11 or higher then you can use below given hook to modify default text

add_filter('wcmamtx_my_account_nav_widget_text','wcmamtx_my_account_nav_widget_text_function',10,1);

function wcmamtx_my_account_nav_widget_text_function($default_text) {
    
    if ( !is_user_logged_in() ) {
            return $default_text;
    }
    
    $current_user = wp_get_current_user();
    
    $user_name= $current_user->display_name; 
    $default_text = 'Hello , '.ucfirst($user_name).'';
    return $default_text;
}

use above give php code snippet . you may use code snippets plugin to inject any extra php code.

Best Regards