Abraham Lincoln: lived 460 years before the episode.
Genghis Khan: lived 1,100 years before the episode.
Surak: lived 1,800-some years before the episode.
Colonel Green: lived 200 years before the episode.
So there's no rhyme or reason as far as time periods go. Far all we know, both Kahless and Zora could have been contemporary to the 23rd century.
You seem to be assuming that the official chronology is correct, despite the fact that it often contradicts the evidence of the episodes.
For Abraham Lincoln (1809-1865) 460 years after his lifetime would be sometime between 2269 and 2325. I presume you are accepting the official date of 2269 for "The Savage Curtain".
When they discuss Kirk and Spock beaming down to the planet:
SCOTT: Lincoln died three centuries ago on a planet hundreds of light years away.
SPOCK: More that direction, Engineer.
So Spock was such a nitpicker that he corrected Scott about the direction to Earth, even though that direction would be constantly changing as the
Enterprise orbited Excalpia.
So Scott's "three centuries" must have been accurate enough for Spock to accept as reasonably accurate by Human standards and accurate enough not to be corrected.
If Spock would accept "three centuries" if it was 300.00 to 300.99 years later, the date would be sometime in 2165 to 2166.
If Spock would accept "three centuries" if it was 275.00 to 325.00 years later, the date would be sometime in 2140 to 2190.
If Spock would accept "three centuries" if it was 266.67 to 333.33 years later, the date would be sometime in 2131.61 to 2198.61
If Spock would accept "three centuries" if it was 250.00 to 350.00 years later, the date would be sometime in 2115 to 2215.
If Spock would accept "three centuries" if it was 225.00 to 375.00 years later, the date would be sometime in 2090 to 2240.
If Spock would accept "three centuries" if it was 200.00 to 400.00 years later, the date would be sometime in 2065 to 2265.
But there would be no possible way for Spock to accept Scott's "three centuries" if the actual time span was over 400 years and if "The Savage Curtain" was after 2265.
In the sickbay in "Where No Man Has Gone Before":
MITCHELL: My love has wings. Slender, feathered things with grace in upswept curve and tapered tip. The Nightingale Woman, written by Phineas Tarbolde on the Canopius planet back in 1996. It's funny you picked that one, Doctor.
DEHNER: Why?
MITCHELL: That's one of the most passionate love sonnets of the past couple of centuries. How do you feel, Doctor?
So Mitchell said that Tarbolde wrote "Nightingale Woman" in the year 1996 in the calendar Mitchell was using. He also said that year 1996 was in "The past couple of centuries". Thus the date of "Where No Man Has Gone Before" must be sometime between 1996 and 2196 (and probably between 2096 and 2196) in the calendar Mitchell was using.
Thus the available evidence does not indicate that the official chronology is correct to put TOS in AD 2265 to 2269.