Which transformation apart from Update strategy can be used to flag the rows for insert, update,delete and reject

While Update Strategy is the primary transformation for flagging rows, Custom (or Custom Transformation) can also be used to set row flags for insert, update, delete, and reject operations. Custom transformations allow you to write procedural code that can manipulate row flags based on complex business logic that might be difficult to express in Update Strategy expressions alone. This provides flexibility when complex conditional logic determines how rows should be treated.