Logitech makes some great mice, but for some reason their MX line only have the device change button on the bottom. I could not deal with that, so for my MX Vertical I wired in a button up top.

This uses a “Kailh Mute button 6*6*7.3mm Silent switch” which I got on AliExpress

The button is held in place by the “Holder” piece which locks into a structural part inside the bottom shell. Then the hole is cut out the top half for the button. The printed button is oversized so may require some shaving off of the bottom to get it to press the button right.