If you know your way around openIV, find the handling.meta file for whatever vehicles you want and changes the value for:
<fCollisionDamageMult value=
the less the value is the less affected the vehicle will be by collisions which will make it harder for the glass to break.
It's 1 of 4 lines that dictate how much damage a vehicle takes overall, I always change those for my favorite vehicles:
<fCollisionDamageMult value=
<fWeaponDamageMult value=
<fDeformationDamageMult value=
<fEngineDamageMult value=
handling.meta file for original game cars are in "update.rpf\common\data"
since handling.meta files for dlc vehicles are updated every now and then, look for them first in "update.rpf\dlc_patch[name of dlc]\common\data" if not then "update\x64\dlcpacks[name of dlc]\common\data"
If you know how to use zmodeler3 and have a license you can make any car's glass bulletproof\bulletresistant like in this mod