Microsoft 365 Cross Tenant Migration

You need a more global solution.
Because:
- you need to migrate content
- you may need to transfer the domain
- you may need to migrate the laptops.

Check Cloudiway solution, it has a global apprach:
You can perform your migration with a solution like this:
https://cloudiway.com/solutions/microsoft-365-cross-tenant-migration

For detaching and reattaching the domain I would suggest to use this feature during the detaching operation
https://cloudiway.com/mailrouting-for-microsoft-365-tenant-to-tenant-migration/

Intune and laptop migration
https://cloudiway.com/solutions/intune-migration/