Comment by stevage

I got this keyboard : https://www.keebart.com/products/3w6 that uses mechanical low profile silent choc switches (Twilight Ambients Silent) and they are quieter than most non-mechanical keyboards. Eg. my Logitech Ergo k860, which uses rubber domes, is louder. Only quieter keyboard I can think of is my MacBook Air but even that can get louder with intensive typing because of a different sound profile - depends on how hard you bottom out - for my typing style chocs are a bit louder.

Realistically nobody would even hear you typing on this unless you're in a quiet room, and there's a ton of mods you can do to get it quieter.

Anyway if you are into solving niche keyboard use cases definitely look into the custom build scene, it's surprisingly easy to build high quality custom solutions, and even easier to find someone to build it for you for few hundred $.

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.

You can get quiet mechanical switches that are comparable to laptop keyboard switches in terms of noise. There's a bit of art to the selection, but there are definitely options.