So ...

As I said, the scheduling feature is definitely not an easily noticeable option ... Let's see where it is ...

And let's start with the Gutenberg editor ...

You need to check out the "Document" tab in the top right corner of the editor screen. On the "Satus & Visibilty" panel you'll notice a "Publish" option ... and you need to click the "Immediately" link:

As a result, a date-picker will be displayed that will allow you to select the date and time when you want to publish the given post:

Once you have selected a future date, the usual "Publish" button will change into "Schedule" ... Click it, and Wordpress will schedule your post accordingly.

Note: if you select a past date, you will back date your published post.

OK. Now let's see the Classic Editor ...