Currently when you are grabbed, all you can do is mash the shove button and shove the zombie away.
How about a second option to mash LMB that breaks out of grab faster by using your current weapon.
For trade-offs vs shove, firearms would consume a bullet and melee weapons would be lost (thrown).
So visually in first person it would look like Resident Evil’s defensive QTEs, functionally it could mimic throwing the melee weapon against the zombie(s) (one handed melee only hits the grabbing zombie while two handed melee hits more?)
I don’t think there’s anything wrong with shoving but I think being able to use your current weapon would add more immersion and flavor.