I have a valid ABTD card. Do I need to get a new card?

no. Holders of a currently valid ABTD card do not need to obtain a K-ETA for ticket issuance.
However, the United States and Canada are temporary member countries and do not provide visa waivers and only guarantee rapid processing through dedicated international airports, so K-ETA must be obtained in advance.
You must obtain K-ETA in advance.