Facebook is described as 'Connect with friends and family, share photos and videos, organize events, and join groups on a cross-platform social network offering messaging, live streaming, and more' and is a leading Social Network in the social & communications category. There are more than 100 alternatives to Facebook for a variety of platforms, including Web-based, Android, iPhone, Self-Hosted and iPad apps. The best Facebook alternative is diaspora*, which is both free and Open Source. Other great apps like Facebook are Mastodon, Minds, VK and Gab.
BuddyPress can be a Facebook alternative, depending on your needs. It's a Wordpress add-on, which means if you self-host or have hosted for you a Wordpress blog or website, you can add BP to enable you to create a social network of your own. Do it on your server and keep your privacy!