To answer your question: No, XLR cables won’t do much, if anything, to improve bass response in that situation. You have a bright room with many hard surfaces. One of your speakers has no wall behind it for bass reinforcement. A sub woofer would help, but again, its a difficult room. Personally, I wouldn’t even try for high quality sound in that room. I’d employ a desktop system, listen in the nearfield and move those components into another room and situation that would support a better listening environment. Best of luck!
P.S. Nice rack!