I just can’t bring myself to back up my 2FA to the cloud. The ‘something you know’ (your password) and ‘something you have’ (your 2FA) mantra doesn’t work any more as you’ve just given the something you have part of it away.
As usual it’s a trade off for convenience Vs security but for me I will use a hardware key where I can or print out the 2FA code and keep it hidden.
I don’t know how authy protects your 2fa backups so maybe they have good enough security for this not to be an issue.