One answer I haven't seen mentioned yet is to use a carrier who lacks a physical presence (e.g. many MVNOs). I'm not sure if the MVNO security infrastructure ca

One answer I haven't seen mentioned yet is to use a carrier who lacks a physical presence (e.g. many MVNOs). I'm not sure if the MVNO security infrastructure can be circumvented by employees at the source network's physical stores, however. E.g. if I use Boost Mobile, can a Verizon store employee override the PIN I've set? Of course the best answer is to not rely on SMS or voice call 2FA, but as others point out, some services only support these insecure options.