A former Apple engineer has created a new client with multi-account support and called it Mimestream. But it is very easy to use, integrates with other features, and has a lot of technical support and many people creating new applications.
You don't have to go to Tutanota or ProtonMail, but any provider is a bit more private than the native Gmail. It is true that if you like privacy you are looking for another type of provider.
Although Apple's native email application is good, it is not as widely used as the all-powerful Gmail.