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.
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 $.
I bought a Keychron mechanical keyboard with its quietest switches and was a bit burnt by the experience - way louder than anything I want to use. But yeah, I believe you that the technology has improved.
Thanks for the info!