As we all know "glass is glass and glass breaks".
You can use this model to replace sony z2 glass back cover.

Test printed and test fitted using Prusament PETG and Prusa MK4.

Flip the print in that manner that smoothness from print table faces phone interior to avoid potential damage of internal components

Note that removing the pane with heatgun like you would do with glass is very bad idea. Instead I would suggest using sharp exacto knife.