No!
But seriously, there is some truth to it - when faced with this problem in an actual game you would need to ask yourself - can I kill? if not, can I kill via ko? if so, can I win the ko fight? if so, (and there’s nothing bigger to play) then you can play, fight the ko and kill the stones. if not then don’t play there - save it for ko threats you can use later.
If you only “try” then you are as likely to end up wasting the potential you can use later. Maybe, the balance of ko threats in the game will change in your favour. Maybe another ko fight will start and you can use this position for threats. Maybe the local position will change and make this something you can kill without fighting the ko. anything can happed over the course of a game!
in summary, for go problems, you just need to assume that if you cannot kill outright then it’s worth finding the ko (or seki) sequence and that will be the “correct” answer