That's what we do at our company FWIW. Lots of people queue up comms to be sent during the start of the other person's business day. It helps a lot especially for folks in other time zones.

As a remote-first company, many of our teams/channels have people spanning five or more timezones. For my team, there is no time that I could send a slack to the channel in which everyone is working (and I think exactly one hour where it’s not 10:30PM-8AM for someone in the channel if everyone is in their home time zone).

Further, I don’t require employees to notify the team if they travel to another time zone temporarily (it’s none of my/our business).

Receiver-side notification settings are the workable answer here IMO. (I don’t care when you respond to the Slack channel; I do care that we can use Slack. Slack has the ability to set your own schedule on notifications already.)

I don’t understand why anyone would have slack open outside of their work hours. And then complain because they lack the self control to turn it off.

I don’t care when the email comes in as I won’t look at it until 8am (assuming I’m working 8-4)