Yes, the simplest solution would probably be to add specific ownership records for each resource into the user_imported_* tables manually. Just specify resource IDs as eaasiID and assign them to user IDs from Keycloak as reported by the migration under:
Mar 15 14:09:06 eaasi-prod docker-compose[1677783]: eaasi-web-api | Importing legacy users into Keycloak...
Mar 15 14:09:07 eaasi-prod docker-compose[1677783]: eaasi-web-api | --> User created: OLD-USER-ID -> NEW-USER-ID
...
The above snippet means, that a legacy user with ID OLD-USER-ID has been mapped to a user in Keycloak with ID NEW-USER-ID, so your tables should now use these newly allocated IDs as userID.
Also, ownership records for different resource kinds should be added to corresponding tables to work properly. Object resources are located at <eaasi-install-dir>/objects and records should be added to table user_imported_content. Images on the other hand are located at <eaasi-install-dir>/minio/data/image-archive/images and records should be added to table user_imported_image. Environments are located at <eaasi-install-dir>/minio/data/image-archive/environments and records should be added for each private environment to table user_imported_environment.