I suppose variety is key here since there’s no obvious answer for this kind of serve.
Pushing short a dead serve with quality is extremely hard to do consistently but mixing it up with flicks, long pushes and side swipes make or break the match.
Tho, I just want to add that even Fan Zhendong couldn’t really do anything against these serves, though, fortunately, my opponents are nowhere near as strong as LSS.
you're observations are correct.
There are simple rules and i am surprised that seemingly more advanced players would tell anybody to push an empty ball. This just tells me that who actuall recommends such things are lacking in the short game, because this simlpy does not work.
dead spin usualyl actually has slightly top spin, because even only the friction of the ball hitting the table twice (on a serve) will generate some kind of top spin.
Pushing such a ball will always go upwards and half-long to long(if we define push by having a bat angle that is more open with the rubber more facing the ceiling than forwards).
A faster empty, slight top spin can be blocked if it has enough power to penetrate the topsheet and sponge and get enough lift via the incoming topspin to guide the ball over the net.
For shorter and lower energy dead spin/slight topspin usually fail to dig enough into the rubber, so that this automatic lift over the net will not work, so you need to do an active movement to have a thick enough contact to not let the ball drop off the bat into the net.
The challenge here is that any active movement with thick enough contact will also drag the ball to that direction. Some serves you can keep short by using the side of the ball to chop down on it, but only because the incoming spin and momentum is enough to guide it back over the net. This is not the case in the scenario described by Robin.
The opponent uses the deliberately to force the open game and there is not much chance to avoid that (if you play inverted).
I think you need to embrace the situation and know that you will get into the open game, so you need to work on your flicks. Be it forehand (more intuitive but less dangerous) or backhand banana. The main point is to have a very closed angle on the backhand banana. Open enough to guide it over the net but close enough to not hit it in a too high arc.
i watched a higher level league match lately where i noticed that the backswing for the backhand flick was basically totally closed (rubber pointing to the table).
TLDR; flick it with a closed angle and medium acceleration to get the minimum thickness of contact needed to engage the topshit and lift it over and use positioning to give the opponent a not that easy opening to loop, but remember he will loop.