As I said, TUC is set after the entire run of DC volume 2. There's a gap of at least six years between TFF and TUC, and DC V2 picks up right after TFF and does not run long enough to fill that entire gap. There are only 12 distinct movie-era storylines (ranging from 1 to 5 issues) in the comic after "The Tabukan Syndrome," which isn't nearly enough to fill the three or more years between it and TUC.
After all, the makers of the comic knew that the crew would retire after TUC, so naturally they chose to keep the series in the lengthy gap between TFF and TUC instead of moving beyond it. And once Margaret Clark took over as editor, she gradually shifted its focus from the movie era back to the TV series era.
As far as I know, the chronologically last story in DC's TOS run is "A Question of Loyalty" in Star Trek Special #2, which features Valeris as a third-year cadet, putting it a year or more before TUC.