What is the best technique to improve removing PETG from the print bed? What is the best technique to improve removing PETG from the print bed?
PETG is known for sticking well to the bed; so well that it does not need a heated bed.  If it weren’t for printing other materials, I would try printing directly on the glass bed instead of a build surface. However, the build surface may help protect the glass from excessive force.
To reduce how strong the PETG sticks to the build surface I’ve reduced the bed temperature to 35 °C. It is easier to remove the skirt and brim by heating the bed up to 90 °C, so that the PETG is soft. However, if one tries to remove the printed object at 90 °C, the printed object is like to distort and ruin.
I did sharpen the putty knife on the top side only. This helps, but it still takes excessive time to remove the print job and clear the bed. The excessive force on the bed from the putty knife seems to increase the need to level the bed. It also seems to affect the flatness of the build surface.
I’m looking for techniques to make it easier and less time consuming to remove the PETG print from the bed.
P.S. Additions after input from answers.

Added keeping the initial Z-height high enough to keep adhesion to the bed from being too high.  This resolved the adhesion to the bed issue, but seemed to make adhesion between layers worse.
Set hot end to 230°C for first layer, then increased hot end temperature to 250°C for better adhesion between layers.
Correctly level your bed. Seriously, that's the answer. PETG does stick well, but it only gets difficult to remove if you're smashing the first layer against the bed with a nozzle that's way too close. With the bed leveled properly - using feeler gauges or test prints and a sub-0.1-mm-precision caliper - I have no trouble taking PETG prints off a buildtak-clone bed. Glass should be easier.
If you already have PETG stuck to a build surface you care about and don't want to risk destroying it, try heat, or alternating heat and cold.