Not working, just tried
There's no ready plugin that can do that as far as I'm concerned,
Usually, they should be set to schedule from the start,
I can think of turnarounds like exporting the posts, then importing them via WP All Import, you can use "Automatic Scheduling" from there,
Or you can create a small Python script that would use WP API (or MySQL), connect to the database & publish the post(s), along with Cron job,
You can use WP-Automatic for this as well, basically by creating a live version of the posts (subdomain) & import the posts every X hour/day,
If you can code (or hire someone to do it), the work should be much easier to do,
I'm pretty sure that won't take much work, that would be better if you have plenty of websites that you need that specific code/plugin for