My automation helpers scripts includes a script for generating a list from a number.
You can then use that list in a repeating group. Put your Create record action inside the repeating group.
This method will use only one automation run to create all of the linked records. It also does not require any additional helper fields.
I wrote up an explanation with screen captures here.
Note that automations can have limited advanced logic. If your automation already has a repeating group or conditional logic, you will not be able to add a new repeating group.