To test this critical aspect of hosting, we include uptime monitoring as part of our review process, and the results show that most web hosts do an excellent job of keeping sites up and running. Sites with uptime problems aren't eligible for high scores, no matter how good the rest of their offering may be. All services suffer ups and downs, sometimes for reasons beyond their control. Those sites that fail to quickly address the problem are penalized accordingly.
If privacy is your number one concern, perhaps you should go with Protonmail. You can upgrade to an email with your domain easily on a web interface under “Protonmail Plus” or “Protonmail Visionary” plans. However, the plans can be rather expensive, as getting only 20 GB storage space could cost you at least €24/user/month/yearly. Most email hosting providers retain your emails for months even after you delete your account. This Swiss email provider will destroy all your data when you delete your account.