You'd have to have people who were provably harmed, in a way that jurors or judges would recognized as harmed. Google will defend themselves vigorously, and likely win. And it would take a long time.

More effective to just leave gmail. It threads conversations and gives you a lot of storage. Other than that it's just email.

There are lots of cheap email options where the only way the provider makes money is by you paying them a small amount of it, not by sifting and analyzing the contents of your email and the relationships between your contacts and correspondents.