Proton Pass has a free tier but the authenticator only comes in paid

Yes you need to pay, unless there is a free plan. 
I use other features from them so it it's all included.

There are definitely better options on Android!

jp305

 for TOTP 2FA on my Android.  Works great.

tech

Bitwarden just launched a new authenticator app | Bitwarden Blog

sefiro

You have to pay for Proton Pass, right?

I have been using [KeePassDX](https://github.com/Kunzisoft/KeePassDX) for TOTP 2FA on my Android.  Works great.