How can I pause the batch image processing in Topaz Gigapixel AI? Why does it run slower overnight?

I have a batch job of a few hundred images. The idea is to run this on my MacBook overnight and pause it occasionally during the day when I need the computer.
I can’t see how I can use it. If I cancel I will then have to reset the job and then it tries to redo all the same images. Seems like a major design flaw to me unless I am missing something.

Also during the day it takes on average 3 minutes for an image to enlarge, but overnight some took well over an hour. Is there something on my MacBook I can do to stop this?