Hi,
I would create a user custom field to store the user level from wordpress.
Then, option 1:
Use the "Profile field based cohort membership" plugin to enrol users in 3 different cohorts.
Then use the "Cohort sync" plugin (I believe it is already in the Moodle core enrolment methods) inside each course to automatically enrol all the users in a cohort (this is run periodically, you decide how to schedule the task).
Option 2:
If you don't mind to have cohorts, I believe you could just use the Auto-enrol plugin (https://moodle.org/plugins/enrol_autoenrol), add the method to the courses and then filter the method directly on the user's custom field (but I did not test this).
I would create a user custom field to store the user level from wordpress.
Then, option 1:
Use the "Profile field based cohort membership" plugin to enrol users in 3 different cohorts.
Then use the "Cohort sync" plugin (I believe it is already in the Moodle core enrolment methods) inside each course to automatically enrol all the users in a cohort (this is run periodically, you decide how to schedule the task).
Option 2:
If you don't mind to have cohorts, I believe you could just use the Auto-enrol plugin (https://moodle.org/plugins/enrol_autoenrol), add the method to the courses and then filter the method directly on the user's custom field (but I did not test this).