I suggest using packaging tape over the broken glass and a ifixit iopener and heating the glass in sections. A heat gun should work also but make sure to not overheat the phone.
When you have heated up one section use a guitar pick or something slim to shimmy underneath the glass and split apart the glue.
If you have a very thin metal tool such as a curved screen metal open that is millimeters thin I would use that but only along the edges and with caution.
Do not try to force your way through the glue as you might cut the wireless charging oil and damage it.
So work in sections heating up the back glass and slowly pushing through the glue until you. Half of the phone done. When moving in to the middle of the phone toward the center be careful of how much you heat it up and force the glue. Once you get past the wireless charging coil you should be fine.
Another piece of advice is make sure you got the tiny piece for the camera lens to replace if you didnt take that off. I suggest getting a new one because the old one can get small pieces of glass stuck on it that is very hard to get off.
Hope I helped somewhat.