Unable to stop Lightroom from going to sleep on iMac

I've been unable to find a solution to this problem with my iMac (Monterey 12.6):

Whenever I try to run a long task in Lightroom, such as transferring a large batch of files, the iMac goes to sleep (black screen) and the task stops.  It only restarts when I wake up the computer again.  Attached is a screen grab of my settings.

I thought turning on "Prevent your Mac from Auto sleep when display is off" would stop this from happening.  This doesn't seem to work as it should.  Or am I missing something?  Tks.