Hey there!
I've seen this problem before! The best thing in these situations is to put packing tape (or something along those lines) over the back glass. Next, use isopropyl alcohol along the edges of the back glass. Then use a suction cup to grab onto the back glass and take it off. I found a good video [link|https://youtu.be/oadjCPSjTVs?si=2UIraehblGSZgtx4&t=44|here] of this being done.
Best of luck!