Restoring RDS snapshot from an unsupported DB engine version

Suppose a MySQL RDS instance was created with engine version 5.7.33 and a backup of it was taken today, with plans to retain the backup for seven years. After seven years, if AWS no longer supports version 5.7.33 and the user wants to restore the snapshot, can they do so? Additionally, will the data be recoverable even if the database engine version is no longer supported? Furthermore, if restoring from the snapshot is not possible, what are some alternative methods for storing backups of an RDS instance for long-term retention?