From left to right:
A 25 or so year old Panja/Phast automation dimmer [Lonmark over RS485].
Inovelli LZW36 [Z-Wave of course]
Aeotec dimmer [Z-Wave]
Shelly 2 load switch [WiFi]
My suggestion/wish/hope would be to use the pill that makes you small (go ask Alice). The LZW36 is… well, large. Aeotec is also Z-Wave, so it is not some issue with Z-Wave implementation. I have not ripped an LZW36 apart yet, but it does not seem like there should be a reason for it to be deeper than the seam about 12-15mm behind the plate.
So why am I using Inovelli?
Not terribly expensive.
Nice LED indicators (though individual LED control would be nicer).
Nice button interface.
Aeotec’s snap-on button interface does not seem well-made to me (lots of flimsy plastic), and buggy.
Shelly does not do physical buttons, so you have to roll your own. On the other hand they are really low cost, so shrinking does not imply cost would go way up.