"Batch processing" usually involves making payments to multiple addresses, all in a single bitcoin transaction. In other words, it means that you will create a transaction with many outputs, each paying a different customer, for example.
In your case, you are trying to consolidate funds (UTXO). The result is similar: a more efficient use of space in blocks and therefore a reduction of the costs for you.
To consolidate all your UTXOs, you can simply send a BISQ transaction to your bitcoin-core portfolio, which completely empties the BISQ portfolio. This should use all your current UTXOs as inputs and create a single output that will be usable from your bitcoin-core portfolio.
It may be worth looking at mempool to complete this transaction at a time when the fees are low, for maximum savings.