Mail doesn't support read receipts?!? OS Monterey v.12.6.1

Just to be clear - read receipts are not standard on Gmail accounts not tied to a business or institution with an administrator...

Request or return a read receipt

This feature is only available if you use Gmail for work or school set up by an administrator. If you use a gmail.com account, read receipts won’t work.

To find out when an email you sent was opened, you can request a read receipt. A read receipt is sent to you as an email with the time and date of when your message was opened.

Want to get more out of Google apps at work or school?  Sign up for a Google Workspace trial at no charge.

Request a read receipt

1. On your computer, open Gmail.
2. Click Compose.
3. Compose your email as you normally would. 
4. At the bottom right, click More options   Request read receipt. 
5. Send your message.

Important: You’ll see any read receipts in your Inbox. The person you sent the message to may have to approve the read receipt before you’re notified.

Return a read receipt

If you receive a message that requests a read receipt, and your organization wants you to approve it first:

1. On your computer, open Gmail.
2. Check your emails as you normally would.
3. If a message tells you a sender has requested a read receipt, choose an option:

• • To send the receipt now, click Send receipts.
  • To send the receipt later, click Not now. You'll be asked to send the receipt the next time you open the message.

Tip: If someone requests a read receipt, but you don't see a message, your receipt was sent automatically.

When receipts aren't returned

Read receipts work across most email systems, but you won't get a read receipt if:

• You send a message to a group mailing list or alias.
• Your administrator restricts receipts to people within your organization or to specific people outside your organization.
• The recipient uses an email program that doesn't sync in real time (like a Post Office Protocol [POP] client that syncs only on demand, or a Google Workspace Sync client).
• The recipient returns a read receipt on an email client using Internet Message Access Protocol (IMAP) and read receipts aren't sent automatically.

Don't rely on receipts to certify delivery

Getting a read receipt doesn't always mean the recipient read your message. How a receipt works depends on which email system your recipient uses.

For example, you may get a read receipt if a person using an IMAP-based email client marks your message as read, but doesn't open it. Some non-IMAP mobile email systems may not return receipts at all.