If you are worried about privacy while using a Google email address and suggest using another email client but the same service, you may misunderstand what privacy means.

Even if Apple Mail can implement on-device, built-in privacy features, that email will go to Google servers, where Google will inspect (literally) everything in your message. They will know 95% to 100% of the same information because Apple doesn't solve all problems magically (a different IP - through Apple Private Relay, assuming you pay for it - doesn't make you private).

If you are worried about your privacy, don’t use Google (or Apple) for email. Instead, move to Proton.me (the preferred option) or Tuta.com (a nice alternative). That was the first real step in starting to de-Google my life, and it has worked (as far as I can say).

This is feedback from an Apple user who has used their devices for the past twenty years.

Finally, if you want even more privacy, you should use Linux instead of Windows, Android, or (sadly) Apple software.