I’ve recently switched most of my old gmail account to ICloud. Extremely easy to use with the iOS and Mac system. I’m (currently) ok with apple handling my email data, much more so than google. Have had no issues whatsoever.

iCloud (or its prior iterations) has had some bad press over the years ago about undisclosed filtering of inbound and outbound email and since then I haven’t considered them for email:

Outbound: https://www.cultofmac.com/103703/apple-may-be-invisibly-filt...

Inbound: https://www.macworld.com/article/2029570/silent-email-filter...