Over and over we learn that the carrier is the weak link in the security chain. What is an effective way to deal with this? I have a Google Voice number which

Over and over we learn that the carrier is the weak link in the security chain. What is an effective way to deal with this? I have a Google Voice number which I use for texts and verification and which forwards to carrier cell number. Taking over the carrier numbewr therefore does nothing and Google support is crappy enough to never allow one to speak with a human representative. Google Voice itself is behind two factor. I don't feel good about the setup, since the second factor is not technically a separate device with Google Voice. It seems better than the alternatives for now. Any other ideas of how to practically eliminate the weak link?