Considering moving my personal email domain to iCloud. I trust Apple more than Google.

https://support.apple.com/en-us/HT212514

Why do you trust Apple more than Google?

Why not consider another service such as Proton instead?

The open web is dead, long live the open web. ⌐◨-◨

https://gabrielayuso.com

Given this I'd think Proton would be a better option than iCloud, for email at least. Wouldn't it?

I think iCould is definitely a good option for people who live in Apple's ecosystem, for sure.

I've considered switching to Proton but I don't use my personal emails enough to justify the move. I use Hey for the UX.

Google has e2ee in Messages as well: https://support.google.com/messages/answer/10262381

Push back on FBI
e2ee in iMessage
Advanced data protection

I think Google is as good or better at the security, but ultimately their business model requires more compromises. 

And yes I know Apple has an ad biz.