Does anyone know why there are no dedicated Authenticator apps made by for example Proton or Bitwarden?
I’m aware that they have TOTP baked into their password managers but you still need to have at least one separate solution to log into your vault.
That’s what I’d recommend. Why Google and not Aegis or another non-Google FOSS app?
Nothing in particular, all my totp was in google authenticator and over the years I migrated them all to lastpass then bitwarden, and the only thing left there is now bitwarden totp.