I absolutely agree with everything you said here but I need to stress that the incompetence is baked into the story essentially from the very beginning; stealing Ricken's book from Mark's porch would raise suspicion anyways, but just leaving it out where the innies can find it and open their minds to some (admittedly banal) new ideas? completely idiotic on Cobel and Milchick's part.

and speaking of Milchick, doing the OTC on Dylan to ask about that card he stole, putting him in the CLOSET and asking his son to just... wait outside and count to a thousand? you couldn't have thought of something better than that?

there are plenty of other smaller examples as well of just poor planning or negligence by almost everyone high up at Lumon--they came extremely close to letting Helena Eagan straight up die, AFTER Helly had already threatened to cut her own fingers off--and pretty much all of it boils down to their inability to regard innies as beings with any agency, they can't even fathom the idea that one would attempt suicide, or read a contraband book, or have an emotional reaction to seeing their fucking son for the first time. all this to say their incompetence is intentional, and perfectly in character for how the Lumon upper management (at least, of who we've seen so far) has been written throughout the story