Here's the Cleanest Solution I was able to repeat and confirm working in 2 different tenants.
Specifically for a recurring meeting from source tenant, migrated to a new tenant, with a new UPN/SMTP domain.
The Message's organizer and some attendees are migrated, some attendees remain in the source tenant.
The source tenant is not changing except for Migrated user accounts in the source are stamped with a forwarding address to the new tenant.
Migrated "Recurring" Teams Meetings are harder to fix. Here's the steps that actually work:
Steps To Fix a Migrated Recurring Teams Meeting (from an Old Tenant to a New Tenant)
1 - The Migrated Organizer Deletes the migrated meeting in Desktop Outlook.
2 - In their Deleted Items folder, Open the deleted meeting.
3 - On the message's menu ribbon, next to the Teams “Meeting Options”, select “Don’t Host Online”.
(This removes the Old Teams Meeting).

4 - Add a New Teams Meeting in the message. (or Zoom or WebEx meeting, or No meeting).
The meeting still has the same times and same attendees.
(The **New Teams Meeting shows, with a new ID for the New Tenant)**(or the other new meeting or no meeting).
5 - Click File, Move to Folder, Select "Calendar".
This saves the meeting in your Calendar and sends the update to the attendees.