LearnDash Drip Course Add-on will help you to drip (unlock) lessons of courses based on typical parameters, based on the terms that user should have their next lesson unlocked on a specific day of the week (for example; on Wednesday each week to be precise).
Features
Using Add-on you will have an option to set the time and date settings for lessons within courses to be available for registered users to view it. Set exact day and time for the lessons to be available for users. Enable sending email notification for users when their lessons are dripped.
Settings
Course settings

Display settings meta box under each course from which you can configure the time and weekday that lessons will be dripped on.

The dripping period will be fixed always (one week).

Select the day you want to make the lessons available at.
Set the exact time you want the lessons to be dripped on, on the specific selected day.

The time format is 24 hours

Set the time to make lessons appears if user enrolled before this hour of the chosen day

Example: If they sign up for the course on a Wednesday before 4 pm, they should have access to their first lesson at 6 pm. If they sign up for the course on a Wednesday after 4 pm, they should gain access to their first lesson the following Wednesday.

Enable/Disable sending emails to users when a lesson is available
Save all data.

WP Cron job will be running to drip each lesson to all users on the configured weekday and time. and send emails on lesson day, that lesson is available.