How to level bed after applying glue stick for bed adhesion
How much glue do you put on it? I use PVA based spray, barely visible, very evenly spread and no problem whatsoever of sticking paper to the glue layer.

Just level the bed as you normally would and apply a sparsely coat of glue, preferably from a spray can.

Having printed literally kilometers of PETG on various build platforms (various glass sheets with or without PVA based glue, Aluminium and PEI), chipping of glass is not something I have seen happening. Perhaps is very low quality glass is used, chipping may occur. Whether your glass is of decent quality can be tested, just print on one side, and if it chips you always have the other side. Printing on PEI with PETG is another chapter, PETG just fuses to PEI and is very difficult to remove, a PVA based glue helps, but still prints were very hard to remove.

Invest in a can of build plate adhesion spray, it lasts long, never gives you problems with adhesion and probably is even cheaper than glue sticks (per mass unit).