I just posted this over in the “Definitive Switch Post” a moment ago, because this question comes up so often:
Don’t be misled by the “MX” in the Cherry MX Low Profile switches, they’re not compatible. Most of the time, when someone refers to “MX” style switches, they mean the normal full-size switches commonly used in most keyboards.
BTW, even the Kailh Choc V2 low profile switches (listed in the UHK Shop) are only compatible with the four keys on the very bottom row of the UHK80’s thumb cluster (Fn2/Space/Mod/Fn2). All the other switches for both the UHK80 and the UHK60 use the full-size MX style hot-swap sockets.
Unfortunately, there’s only ONE “low-ish” profile switch confirmed to be compatible with standard MX style switch sockets (two variants - linear & tactile):