Would advise against plucking, like you said, that could harm the zoa. From your pic, it seems like there’s a space between the frag plug & zoas, you can try to slit a penknife underneath & try to wedge it up. Try not to damage the zoas in the process. If you have to cut into tissue, cut as close as to the frag plug as possible so that you don’t damage the stolon or zoas polyp. Also, if you just got the frag today, suggest to frag it after a day or two after it has settled in your tank