Look up “bunker run” “hathor” or in this specific case “ASD or Onyx facility” on like YouTube. Don’t buy armor. Do one run of any of these and you’ll have 20 full sets just from npcs you’ll kill. This set comes out of chests that are scattered around the ASD facilities. Not all chests can be opened, but once you do a few runs you’ll learn to spot which ones you can and can’t open.