I still don’t think your first paragraph is correct. Attempts and endeavors are covered under these statutes. The pictures below show the relevant discussion of the statutes from the report. The idea that obstruction reaches “all corrupt conduct capable of producing...” seems like a very broad definition that might not be shared by all courts, but the other two pages are harder to work around.
By “presumed facts” I’m referring to the facts stated in the report. I’m presuming that to be true until it’s refuted by someone reliable.
Honestly, my recollection of the section on what Trump was told in this specific instance is that I was not satisfied by what the report said about what he was told. It seemed to lead the reader to the conclusion that he was told he should direct issues with the investigation to his personal attorney because McGahn felt he had become a witness to a potential crime (firing of Comey), but it did not say this explicitly. It may be that the notes they had were not sufficient to find more and the witnesses did not remember.
Ironically, the report does detail a number of conversations somewhat similar to the example you give here, though. At every turn he is counseled by people like Bannon, McGahn, Chris Cristy, and likely his own lawyers, to leave it alone.