Having Top Secret SCI clearance does not give you immediate access to every SAP you request to be read into. Most people are not read into more that a dozen SAPs.
I’ll also point out that if Grusch was an unexceptional IC officer, the pentagon would easily be able to discredit him as such. To date, the pentagon has not attempted to say anything about Grusch’s credibility. Many reporters have stated on the record that Grusch is very well regarded as a high level intelligence official.
What evidence do you have that this guy was not an exceptional officer, other than maybe you yourself were not exceptional?