It's been a while, and I can't access my copy at the moment, but wasn't the Dreadnought not yet launched according to the SFTM? I thought it was on the drawing board as the next planned class to launch?TOS was implicitly consistent with its writers’ bible in that nobody every tried to introduce something like the Federation-class dreadnought FJ would propose after the fact, not to mention that Kirk’s “only twelve like it in the fleet” would’ve been somewhat deflated if it was just a count with no implied precedence.
We know the Dreadnought Entente exists as of TMP, but it feels like the class was pretty much obsolete as soon as it was launched.
Either way, it doesn't factor into TOS or contradict the Constitution being the premier Starfleet design. Nor does the Crossfield.