We used coinbase for over a year with 2fa and it was perfectly fine.
This is in direct contradiction with your question! Every single transaction you have sent using Coinbase are already linked together and to your account and your identity. It would be trivial for anyone with legit beef to acquire the link too.
That goes with any other centralized services.
I'm not worried about law enforcement, just regular snoopers who would be unable to force Coinbase to turnover data. How could a person link the transactions, they can only see that they came from Coinbase but cannot see which of the millions of Coinbase users sent it and cannot see that these transactions came from the same user. Am I wrong about this?