You might be able to handle this on the MTA level. I checked and mailgun and mandrill both do not support queueing outbound email for a scheduled period each day. I googled a bit but could not find anything (or the right combination of keywords) to find a solution for you.
I think France at some point had a law that businesses had to prevent their employees from emailing outside work hours - I think that might be a use case for this, but I am assuming it’s no longer the case.
But otherwise generally I’m not understanding your purpose here and it’s hard for us to help you without understanding better what you’re trying to achieve. Email is designed to be delivered on a timely basis. If a password reset email doesn’t arrive for 10 hours, your users are going to think your site is broken. Those users who do not want to engage after hours can just go to bed and read the emails when they wake up in the morn.