@AToxicMuffin It's not the platform it's the input type.. My config screen looks like this since I'm on PC. I assume you have something similar on the console. Just set Crossplay to Gamepad Only and Input Method to Gamepad. This should eliminate the mouse people regardless of platform.
@Tkeller1321 I did this yesterday for the heck of it.. Biggest problem I had was getting the slay after the grab before an ally did. I used only Vortex Grip and was playing training siege matches. Most of the matches I had live teammates so they kept taking the kills. Eventually I got a match with 4 bot teammates. They were stealing the kills too but since I could delay the match more I had more time to do it and finished the challenge.
Bottom line is you have to get the slay after the grab within 5s of grabbing them. Hope this helps.
Since the ult is in there too you can overpower from a distance but don't finish kill. Then grab then slay - away from your teammates. Hopefully they don't follow you
Edit: I just looked at what it took - 6 total matches to do all of it. The top match was just to finish the ult portion - I used storm for that and bought morale boost. The one where I died was the one that did most of the grab slays.
This has sadly always been the case for the switch version of the game. But i have noticed a drop in crashes since the "instant capture feature" was disabled from the switch version (still want it to come back tho)