Realistic 4K Portrait Enhancement

I have a single portrait that needs a careful, natural lift. The main goal is to raise it to true 4K quality while keeping every facial detail—skin tone, hairstyle, and all features—exactly as they appear now. Where I want you to focus most is brightness; I feel the image is a bit flat and could benefit from a subtle boost in exposure and overall light balance. At the same time, the background lighting has to stay just as it is, so any adjustments must leave that area untouched. Beyond the brightness work, I also need clean-up: remove any visible noise, refine details, and add gentle sharpness so the final file looks crisp on a large screen and can double as a wallpaper. Absolutely no filters, overlays, or AI face tweaking—this must look like the original shot, only better. Deliverables • One high-resolution (4K) version of the photo in PNG or JPG • Natural, realistic enhancement only—no graphics or artificial effects • Quick turnaround is appreciated so I can start using the image right away