lowering VE at low kPa

Hello,
What happens if I lower the VE values or even set them to 0 at lower kPa in the engine braking region, particularly at higher rpm 2000+ ? Normally there is DE that kicks in gradually. Will it just make the engine braking react quickly and violently or could be potentially dangerous to the engine? Also in that region the spark advance is high which some say it even has a braking effect if that’s true, it’s common to make set the spark at higher value for braking or at least reducing torque.
Thank you