While loading records of count 300000, I'm using flow control option with the following configuration.
Batch count of 10 (Also attached screenshot for your reference)
Flow control option:
No of units as 10
Run as batches of 10 docs (Attached screenshot for your reference)
Time taken to load 300000 records is more than 12 hours.
Please check the attached screenshot of the process I'm using.
Please let me know if there is any other process or a better configuration which can reduce the loading time.