Hello @monika and welcome to Microsoft Q&A.
In my opinion, you should look at Synapse, rather than Data Factory.
Synapse contains most of Data Factory features, but also has notebooks to run custom Pyspark or SQL code. This is useful for the transformations Data Factory is not enough for. Databricks also has these notebooks and is worth looking into. Synapse also is closely integrated with Azure Data Lake Store Gen2.
The Spark pools of Databricks and Synapse are meant for more volume than the Function App / Logic App.