My Windows 10 machine has only 16gb. My biggest images are 30.1 megapixels. I have no memory problems using Bridge+ACR+Photoshop.
You say "I made 200 jpegs half the size and saved them." We are not sure how you did that, but it looks like you used the Batch Process inside Photoshop? Don't do that. There are better ways. Use the Image Processor. Or just use ACR. Open 200 jpegs in ACR, click "Save Images", set your options and go. Or do it all within Lightroom.
I regularly process 200+ images to create downsized jpegs from TIFs for web posting. No memory problems like you describe.
Even the old, antiquated Batch Process in Photoshop has no problems like you describe on my Windows machine. Maybe a Mac only problem?