They remain yours!
If you purchased courses directly prior to memberships launching or transferred single purchased courses from Udemy, they will remain yours. You will continue to have access to previous course and bundle purchases after you've subscribed to A Cloud Guru Memberships.
What If I cancel my membership?
If you decide to cancel your membership, you will retain access to the courses you purchased. However, you will not have access to membership-specific features, such as Hands On Labs, Exam Simulator, and Release Review, or courses that you did not purchase before having a membership.
If you need help migrating courses from Udemy, check out this article!