It would be great if you could copy, sorry, I mean get inspired by the Superhuman mail app.
For example: To hide/remind yourself about an email, you can simply hit CMD + H, and a little popup like macOS's Spotlight shows up, and you type "Tomorrow 8 am" and boom. You're done.
Also, please show emails that were snoozed until a specific time at that time. It doesn't help if the email is 20 emails down and just shows up as unread again.
Seriously, just sign up for Superhuman and try it. Then bring it to Apple Mail and thank me later. You could easily win over a massive amount of Superhuman users.
For me, Superhuman doesn't work because they only support Gmail. Otherwise, I would never look back.
Thanks for your consideration.
MSM