True, but a major part of his decline is probably due to interceptions, of which it appears half were made by playing a position where a deflected ball came his way under Flores. I presume this was due to the defensive formations Flores used.
Then he got hurt and was limited in his capability for a while.
Now he is playing in a different defensive system with different results. It's the change in systems that is affecting his stats more than his personal skill set.
I feel he was over-rated before and slightly under-rated now. Expectations don't make the player in a team sport, due to different coaching regimes getting different results.
Look at Mostert, as an example of the exact opposite trajectory, compared to "X". He is the same runner, but the offense now opens holes, and our offensive play calling is greatly improved.
That should clear the mystery up, because there never was a mystery! There was only a false set of expectations based on the results of players on the same team under different coaching regimes.