Problems with the keys on my KK S88 keyboard

TackEm

Hello, my KK S88 mk2 keyboard has a key that has almost no mechanical velocity (I'm talking about touch and not an electronic problem). It sinks faster, does not have the same touch, the same sensitivity as the others and it is really very unpleasant. By the way, I find these keyboards much too fragile and unreliable given the price you have to spend to buy them. The manufacturing quality is not up to par. In short, after watching a lot of tutorials on this subject, it is certainly a lack of grease that gives resistance to the keys of an S88. So I will take it apart to put grease back on all my keys (it is no longer under warranty). On the other hand, I have a doubt about the right grease to use, does anyone have any advice, a reference to give me? Thank you