Comment by joshvm

You can get switches that aren't any louder than typing on a laptop, these days "clicky" is just sub-category. The low profile 'choc' switches from Kailh are probably a good option to try.

https://www.youtube.com/watch?v=WHAK1kJtMVQ - have a listen. Some of them are inaudible under a mic, but really you need to buy a grab bag and play around at home to see what works.