That’s a good point about about making Trump “clueless” for letting Sessions start the job. I thought about that and it is a thread of consideration.
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.