If a module start date for the new academic year is not entered into SITS when the Moodle 4 module is created, it will become available to students on the following dates:
GEN modules (which take enrolments from business rules) and MDL modules (which take enrolments from meta links) are set to Hidden by default and you will need to manually make these visible in time for the start of the academic year.
If you want the module to become visible at a certain date in the future you will need to add/amend the Module start date.
Scroll to the end of the page and select Save and display.