I have seen no evidence for or against Sessions being such a chess master. The lack of apparent activity isn’t evidence, really - it is the absence of evidence.
Sessions is either working hard behind the scenes as you aver, or he is doing nothing. Time alone will tell, but if he is sitting on his hands as many believe, time will tend to magnify the effects of such negligence.
I do not know what the real situation is, but I will point to one sign that little is happening - there have been no leaks from the deep state that any of them have gotten into any trouble. The deep state is not loyal to the elected government - it is only loyal to itself.
I pray that those who actually know what is happening are guiding this along a fruitful path. The alternative is for a Tree of Liberty type of reset for the country - which is a nightmare for everyone.
I’m encouraged, because his critics keep wondering “why doesn’t he convene a grand jury,” and grand juries are secret tribunals. If one was convened, it’s possible that that is unknown, provided that the prosecutor in charge is discreet. But mainly because there seems to be some sort of coordination between Trump and Sessions, like an Abbott and Costello routine, outwardly adversarial, but really one dovetailing into the other.
“Who’s on first?”
“I dunno.”
“Third base!”
“Why aren’t you investigating Rosenstein?”
“I won’t let politics improperly influence my actions as AG”
Media: “Yay, Sessions!”
Then the net tightens on Rosenstein.