This has been one of the wrong mind set the new beginner in the cryptocurrency space are failing to understand, the backing up seedphase of a wallet on google drive is like making it more faster an easier for scammer to attack the wallet,
When we talked about avoid a third party, this does not only applies to those you have a physical contact with that can steal your coins, any online centralized platform is also a third party and should not be allowed to have the opportunity of holding on our private keys, they are not saving them, because they have a central server all these information are stored and they can get across to them at anytime as they demands.