Login to your admin panel (https://admin.google.com/?action_id=SE_SELF_TRANSITION&utm_source=helpcenter) to confirm that your account is for personal use and keep the Legacy G Suite plan going.
Updated Support Page with details: https://support.google.com/a/answer/2855120?hl=en
A second Support Page (https://support.google.com/a/answer/60217#faq) indicates that "You can continue using your custom domain with Gmail, retain access to no-cost Google services such as Google Drive and Google Meet, and keep your purchases and data."