I know Matias made a nice switch, but if the key were a bit more stable (less wobbly) or the keycap didn't touch the switch housing I bet it would be near dead silent. The mechanism itself is ridiculously quiet.
As the Matias guy told us earlier, there is nothing to stop us from trying O-Rings to see if it improves the dampening.
I removed one keycap and played with the switch. I don't think it is the keycaps itself that is wobbly. The keycap seams pretty well attached to the "shaft".
It is more likely the tolerance in the switch itself.

This is not an actual Matias switch, but just to illustrate what I mean. On the Matias I noticed that the white piece had significant side play in the black housing. Enough to explain what you called wobbly.
We can have Matias to confirm, but I suspect the keycap never touch the black housing. Most of the sound we hear is the white part hitting the housing and reverberating in the keycap. I'm not even sure O-Ring would reduce it. That kind of tolerance is probably required to reduce friction and make sure the switch performs well cycle after cycle after cycle x 40 million times

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