The lock and unlock door functions on my key fob have been lagging for quite some time now. I have to press either function for about 5 seconds before the car receives the signal and performs the command. I changed the battery a while back, it sped up a little bit, but went back to the almost exact state. So I figured doing a little research online.
It turns out that the connection between the circuit board and the button wears out after some time of usage. So I cut two pieces of aluminum foil into the shape of the buttons and tucked them between the buttons and keyboard (make sure the foils themselves don’t come into contact with each other). It worked like a miracle, as if this key fob is a fresh one I just got from the dealer.