Yes, after deleting an SQL Server instance, the backup files are typically still retained. Backup files are usually stored in a separate location, such as a local disk, network share, or cloud storage, and are not automatically deleted when the SQL Server instance is removed. The retention of backup files depends on the backup strategy and the storage configuration you have set up.
For example, if you have configured your SQL Server to back up databases to a specific folder on a network drive, those backup files will remain accessible even after the SQL Server instance is deleted. Similarly, if you are using cloud-based backup solutions, the backups are stored in the cloud and will persist unless you explicitly delete them.
In the context of cloud services, if you are using a managed database service, such as Tencent Cloud's Database for SQL Server, the service may provide automated backup options. These backups are stored in the cloud and can be retained according to the backup retention policy you configure. Even if you delete the database instance, the backups can still be accessed and restored if needed, provided they are within the retention period and you have the necessary permissions.