Can't OP move to Cloud Identity Free to keep access to most of the free services[1]? They wouldn't have access to Workspace-specific services like Gmail and Google Calendar, but they would still have access to Google Drive, Docs, Sheets, Slides, Keep, and Meet. I assume other non-Workspace services like Google Play will also stay available.
1. https://support.google.com/cloudidentity/answer/7319251