just press 1 and to knife press 3
my quickswitch is binded to mouse4 and the FK2 buttons are very small so its a pain in the ass. i suggest binding it to spacebar
You can use this for awp, it will switch to knife then back to awp with just one press.
bind "alt" "use weapon_knife;use weapon_awp;use weapon_ssg08"
alias +knife slot3
alias -knife lastinv
bind f +knife
Have you tried typing the command of switching weapon twice in the bind?