If you’re looking to continue on and replace the speaker mesh, take a look at the camera/cable replacement guide.
iPhone 7 Plus の正面カメラとセンサーケーブルの交換
They mention separate the top edge last to prevent antenna damage. I tried to be very careful but still ended up damaging 1 of three antennas. The antennas are directly under the glue and aren’t really that fragile. They key is heat. I was trying to be careful that the glue wasn’t hot enough anymore. If the glue is nice and soft it’ll easily separate from the antenna. Too cold and the antenna will stay with the screen…