CloudM Migrate supports multi-domain migrations. This means you can migrate primary and secondary domain users from the source Google Workspace instance into primary or secondary domain users in the destination.
You can now specify full primary SMTP email addresses in your ‘User/Resources’ page in the Export Name and/or Import Name fields
Next, on your ‘General Migration Settings’ on page 4, you can specify domain and (if required) address replacements.
See https://support.cloudm.co/hc/en-us/articles/360008400360-Domain-Address-Replacements for more information.
Be aware that attempting check users or migration and then changing any Import Name consumes a license for each unique Import Name. Please visit the How is CloudM Migrate licensed? How are licenses consumed? article for more information on how licenses are consumed.