I have the OBS engine 100w which is silent, but the screen makes a cracking noise every time i touch the fire button, also saw that the Coolfire z80 seems silent but its only a 18650 sadly, i puff around 800 times a day (low w mtl) so i would prefer a dual 18650 or single 21700.
Think i was lucky with my 26650 rebel dna75c that it had a silent button, 4 years later it fell and the casing broke, ordered a 21700 rebel but that button had a loud click, swapped the pcb's and it was fine till that one fell too.. funny how my 2 most expensive mods broke from falling while the cheap ones before and after never fell down once, granted the 3d printed nylon is really light but drop it and it will break something, in my case the housing first and the button supports on the 2nd.
Tried the Geekvape aegis max as well, you have loud and then you have this, that click probably echoes in an entire room its so loud.