[3Putt]

I had the same slump. Driver ok, short game ok, Irons, not ok. I changed from Single Wrist Action to Standard Wrist Action (Sequenced Release) and it was over. How stupid was that. Make sure that the Back of the Iron and Shaft are laying flat against that plane in the downswing and release. A Flat Wrist is not a Flat wrist. But, that's probably not your problem.

My intent was not to get into the mechanics, more the mind's response to the mechanics. But your comment re sequenced release is perfect. What has happened throughout this slump is something like this:
swing 1 - for whatever reason I negelect to "roll" into impact. Massive, weak push.
swing 2 - my mind/body won't let that happen again. Smother hook.
swing 3 - paralysis

3Putt