My phone still wouldn't fit, so made one even wider.

Phone in question is iPhone 11 Pro Max with a case. Total phone width including case measures 12.3MM and it fits perfect.

This is my first make so its not perfect, but it does the job!

Printed using CR6 SE
I printed with 35% infill
0.2mm layer height with supports

You need to lay the model flat on the glass by either the left or right hand side (See pictures).