With respect to using a capacitor to augment available current for operating the gate lock:

First, there is the assumption that the lock operates from a DC drive. I have no depth of installer experience here, but just listening to the action as I enter various spaces, many locks operate from AC. Of course, as the installer you would have control over this point.

Second, capacitor charging and support times are a consideration. One should not assume that the door operator (the human) will instantly yank the door open after the lock is enabled. My guess is that several seconds of support would be appropriate. Now, what happens if the person failed to meet the timing window and must then wait until the capacitor recharges before the next attempt?