Hello,
there is only one possible solution for this. edit the role of the instructor and remove the
edit_posts capability.
this could be done by using any third party plugin which allows capability edit for the users.
have a look on codex:
https://wordpress.org/support/article/roles-and-capabilities/
if you do this then the instructor won't be able to perform the desired action as it is intended to perform as a mentor.
you could try these settings:
set these:
LMS -> Settings -> Force Administrator Approval on every setting
WPLMS -> Course Manager -> Admin Approval For Course --> Yes, require approval.
This setting works fine, please make sure you are testing this as an instructor.
Also, check the course as an admin because when the instructor clicks on publishing it is not published but admin has to publish it.