Thanks for sharing the details! Illustrator doesn’t have a hard file size limit for JPEG exports, but issues like this can sometimes happen with complex files or limited system resources.
Could you try flattening the artwork before exporting and see if that helps? You might also try exporting just a portion of the artwork at 300dpi to check if it goes through successfully.
Also, could you let me know the exact version of Illustrator you're using (for example, 29.4.1) and your Windows version? And if you're okay with it, feel free to share one of the files that's giving you trouble so that I can test it on my end.
Looking forward to hearing back from you.
Abhishek