I could barely get the thing open and ended up cutting the contacts off
Oh eep, sorry! You need to use a pair of small screwdrivers or similar tools, just slide them between the housing pieces from the top, and pry the parts a little it apart, and then tilt them inward toward the top housing and lift up a bit. Once you get the hang of it it’s pretty quick and painless, but yeah, it can be tricky to figure out at first.
There are some videos and threads somewhere about opening Alps switches and various clones, but I’m not sure if there’s any perfect explanation online.