Reminder that services such as
Authy can be easily breached if you're a victim to
SIM swapping. These services should not be used if you're suspicious that someone may perform this attack on you. Social engineering is what causes most breaches, not actual "hacking" that you see on CSI Miami. Here are some simplistic recommendations for authenicators that are entirely offline.
Varying on your threat level, Authy is "fine". Personally I would disable multi-device recovery, because that effectively is as weak as SMS authenication. If you're high risk, it's advisable that you research into
physical tokens that are programmable.