If you care about your privacy you shouldn't use any Google's product, no matter how good they are. It's how the company make its income, using your privacy.... Who knows if in 10 years we learn that in fact, it was another shady product
I have read Authy is far better than Google Authenticator.


You can use a USB like U2F Zero as long you don't lose it you're good to go https://www.u2fzero.com/
... and it's open source https://github.com/conorpp/u2f-zero