G Suite Education – Can Administrators Monitor Email?

Yes they can.

Data access by your administrator or service provider

[...] It’s important to note that your administrator has access to any data you store in this account, including your email. Please read the Google Privacy Policy for more information.

And in the G Suite Administrator Help:

Which of my users can access other users' accounts?

Per your domain’s Customer Agreement, G Suite administrators for a domain can access all user accounts and the associated data, as described in our Privacy Policy.

You can also read this disclaimer in the Privacy Policy:

Information we share

If your Google Account is managed for you by a domain administrator (for example, for G Suite users) then your domain administrator and resellers who provide user support to your organization will have access to your Google Account information (including your email and other data).

Doesn't really matter which version of G Suite you are using, the administrator(s) will be able to access (and read) your emails.