quick release clamps for fixing a standing desk to wall

I just installed an IKEA SKARSTA. In the top position it wobbles a lot when I type, sufficiently to be annoying to unusable. My quick solution was to add 1 bracket at each end and screw them on to the wall.

But now I have a standing desk that’s no longer adjustable. I was thinking of some kind of hold down clams that I could lock/unlock when the desk is up (it will have 2 positions). Something like:

Simple schematic, top view

Can anyone suggest a type of clamp that would work in this case ? The goal would be to force the desk against the wall.

PS: The wobble comes from the extending mechanism, there is a lot of play between the fixed and mobile part of the extending legs, and I went to the IKEA and the show room model has the same issue. There is no fixing it.