BBR may not be perfect but it sure is an improvement for Starlink over Cubic. I switched to it on a server I connect to frequently from Starlink and got a 2x performance improvement on TCP connections. Before, big file transfers would regularly bounce between 5 Mbytes/s and 12. After it'd hold a steady 12. Which is what you'd expect given Starlink's high packet loss rate (0.5% for me) and how TCP congestion control traditionally works.