This one was a different episode. You can’t exactly say it’s a problem solving for Supergirl but rather for the DA.
Doing some tests and setting a trap Maxwell Lord made an almost similar Kryptonite but it doesn’t weaken but change personality and behaviour.
This made Supergirl be the bad person and if you ever wondered how Superhirl would fit like a Villain we saw it here.
But now we have a new problem which is the Martian showed up in public.
Another episode of time wasting and a mere 5 minutes of actual story.