It’s clear to me (and of course, I can ALWAYS be wrong!) that the apparently bumblingness of Sessions, and Trump’s criticism of him, was a ploy to keep the derps completely in the dark as to the plan to destroy them.
The derps could go about their merry business - continuing to plot, conspire and bad generally treasonous - thinking that Trump picked a doddering clueless AG, and was helpless to fire him and get a “better” one.
Being willing to look clueless in order to further the plan is something Trump does a lot, and sometimes those under him.
“Look weak when you are strong” - Sun Tzu.
And Sessions was doing tremendous stuff behind the scenes, some of which we know about, and some not.
I'm with you on this little J. Misdirection is the key to a good magic act. Barr keeps saying we are going to investigate but, I believe those have been going on for some time.