If your actions have no effect or ability to alter someone's eternal fate and get them to reconcile with God, then they are pretty meaningless, no?
So those are the options to your mind, either I'm responsible for another person's salvation or my actions are without consequence.
You asked if I could save someone. Of course not, but my witness can be used by God to bear fruit. God frequently uses the willing instrument of those who love Him. Also, is your education wasted if it impacts and betters only you or is it useless to the extent it only does that, assuming that's possible? Of course not.
God is calling on you to perform an empty action.
No, you just keep doing your darndest to frame it so that's the outcome. Supra. Your premise was flawed.