I'd just go on a cut and make sure to lift weights twice a week and after your belly gets small enough, you can try to add more size. You may find after your cut though, that your chest will appear bigger
Either way is fine. Though there's really no good reason to focus 100% on one over the other. You absolutely can do both.
It depends on training experience. If you're relatively experienced, it's not going to happen. If you're a noob to resistance training, you can do both at the same time.