In the market for an email provider - business level reliability needed
 

Atm, I am using Office 365 essentials plan 1 (I think).

The interface is clunky and horrendus, I mainly rely on it as the web interface has the option to request delivery receipts (something FM promised a long time ago but have never implemented or even a delivery log section in the settings).

Delivery receipts are crucial for my purposes.

The O365 plan expires next month and I am considering changing providers...

Any thoughts please?

(Luxsci which claims to be business grade and probably is, I never did like their email and I don't think they are all that so not considering them.)

I would look into Skiff business plan, Mailbox or Tuta Business, but I don´t know if they have delivery receipts... However this does not always work, my email provider, Posteo, allows me to disable delivery receipts, nobody gets notified whether I receive their email or not. Please post back which one you picked if you can, just curious as I don´t have the time to do the research into these services myself, I could only tell you in detail about the one I use and they have no business plan.

Google Workspace. People like to hate on Google, but they are the best at email.
https://support.google.com/mail/answer/9413651?hl=en

Those seem like solid recommendations to be sure (though there are others).

These are read receipts, not delivery receipts. FM has these.
By protocol, if an email is not delivered the sender is notified that it was not delivered. But delivery can sometimes take several hours or even days, and not getting a non-delivery message doesn't mean the email was delivered until several days after it was sent.

Am I wrong that delivery receipts depend on the recipients server responding with that message, and many just don't?

I think it depends more on the recipient's client settings.
And I think a "delivery receipt" would be some kind of message the sender's system sends back when delivery outside the system is completed.

My understanding is that the recipient's email server must support delivery receipts, and if the receiving server doesn't support the delivery receipt you won't get any confirmation sent back to you, the sender.

Or an email where there is an option in settings to check delivery logs.

I use Google Workspace and Zoho.....kind of like Zoho better