I'd say that "Maybe" Goff is better these days at reading and adjusting to the 5-1 over front and quarters coverage behind strategy that was used against him in the super bowl and actually conceived of by the Lions that year to shut the Rams offense down.
I know it was used over and over again by teams that had the personnel to pull it off (Dolphins for one) and it was frustrating Goff and Mcvay until Goff's final days with the Rams.
It's possible that he's doing a better job with that and maybe the Lions coaches were able to help him unlock what he needed to get better against it. The Rams really didn't have an answer for it at the time, or maybe Goff wasn't actually taking to what they were trying to teach him to look for. Something was definitely off and Mcvay decided it was time to move on.
I'm not sure exactly, I don't follow Lions football all that close.