Google used to read your email, granted this was an automated process done by computers but it is illegal in the U.S. to read someone else's mail. Google has dropped this practice, but it says a lot about how they view users.
If you still want to use gmail, they do have top security teams that make gmail very secure, then check out their Advanced Protection
Outlook is owned by Microsoft and Yahoo has had so many data breaches it should be out of business.
Free = You Are The Product
Free services make you the product and collect your data
They Read Your Email
Many free email providers read your email
Some services encrypt like Gmail, but email is not safe overall
Scammers use official looking domain names to fool people