I think that Barr was appointed as a failed attempt by Trump at a truce with the Deep (Shallow) State and the CIA. I don't think Trump was fooled by him, Barr was just given a long leash, a bloody thorn that Trump had to tolerate.
Trump clearly has now set up a firewall against Barr, DOJ, FBI and CIA using military assets and military intelligence. It is likely it was done in secret, but took some time to implement.
It could be that appointing Barr was a misdirect and a holding action, while Trump consolidated alternate resources.
Barr clearly has been fucking Trump the whole time with perceived impunity.
I think Trump knew the DOJ was corrupt and decided to build his master plan without them. So, keep Barr in place for appearances and then fire his ass right as the EO report comes out later this week.
It goes without saying that Biden/Harris clown show will be a disaster squared, but I think Trump missed an opportunity to change a lot of things.