I have some good news!
So I put flour around the large appliances right after I discovered she was missing. Finally, today, there was a flour trail showing that she exited the flour circle around the oven! This means she spent the entirety of last week camped under and around the oven. I've blocked off the space under there, so she can't return, now.
It seems she headed in the direction of the dishwasher, so I bet she is under there now. I put a flour circle around that, and moved some water, a mouse in a snake trap thing, and some humid hides right nearby. Now that I know she is alive and vaguely where she is, hopefully I can finally nab her!
I also finished setting up the tub enclosure, so I'll have a nice and secure place to put her when I find her