As I recall the hard limit is a file with 300,000 pixels on a side. You're not nearing that.
Files the size you're working with need a LOT of computer resources..
32 GB may be the most RAM you can put in your particular computer, but it's certainly not the max any computer could take. You'll also want hundreds of GB of free disk space - maybe thousands.
Remember that anything you do creates a history state, where the image has to be copied to a new block of RAM. Minimizing your History states could help reduce the amount of data that's swapped to scratch files.
A file of tens of gigabytes in size is probably nearing the top of what's practical to work with using modern computers. You'll need to be patient.
-Noel