About .BAK native backups, yes you can restore them on another SQL MI cross subscription. However, if you want to restore a .BAK native backup to an Azure SQL VM or SQL Server (on-premise), the my suggestion is to use bacpacs instead because of the issues explained on this article.
About the bacpacs/dacpacs, you can restore a bacpac on another SQL MI instance and on another SQL Server instance (Azure VM or on-premises).
About TDE and bacpacs, when you export a TDE-protected database as bacpac, the exported content of the database isn't encrypted. This exported content is stored in unencrypted BACPAC files. Be sure to protect the BACPAC files appropriately and enable TDE after import of the new database is finished.