Harbor - one private inbox for all your email.
Harbor shows the email accounts you connect (Gmail, Microsoft 365 work or school accounts, and Zoho Mail) in one place on your phone, and sorts them so the messages that need a reply or an action come first.
It reads your mail so it can show and sort it. It only replies, forwards, archives, marks, or deletes a message when you tap the button to do it, and only after you have turned that on for the account.
Harbor is a private app for a small group of known users, not a public service. Each person has their own separate copy.
Contact: the person who invited you.