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Authy got hacked, and 33 million user phone numbers were stolen
(appleinsider.com)
This is a most excellent place for technology news and articles.
And as soon as I learned about that I stopped using it. Turns out it was the right choice - since then more then one company had breaches where authenticator seeds extracted from a google account were used to bypass 2fa.
It's completely optional to connect a Google account. You can always back them up using the QR code (just take a picture with another device)