The butterfly guard is a very powerful position, but if you know what to do, then you can defend the sweep, smash the guard, and take the back. This technique from the Rolling Backtakes for Everyone instructional (https://www.grapplearts.com/rollingbacktakes) is one of my very favorite ways to do just that, and if I can do it as a 54-year-old man with a hip replacement, then you can do it too!