* First, ex-president Yoon was a drunkard idiot: he believed that he was surrounded by evil commies, who manipulated legislative election of 2024 to give the opposing Democratic (Minjoo) party a resounding victory, who would (in Yoon's mind) go on to sell the country to China. Or something like that. So he decided that the only way to "save Korea" from those evil commies is to declare martial law and purge the commies.
* South Korea always had its share of evangelical protestant far right wingers, and sadly they have now become rabid supporters of Yoon (even now!) - Korea's version of MAGA. They maintain that all the delusional shit Yoon said are true, Korea is on the verge of falling to communism, and the only way to save Korea is put the commie usurper Lee into prison and reinstate Yoon as the rightful president of SK.
* Yoon did try to provoke North Korea into attacking SK, presumably to use it as a pretext for his martial law, by deliberately flying drones into NK without precaution so that North Korea could find out. Recently, the court sentenced Yoon 30 years for that [1] (trying to start a war is a serious crime!), though the case is still ongoing. FWIW, North Korea didn't take the bait (thank god) - they have impeccable survival instincts.
* So I think many parts of the RT article is true (I only skimmed it), though the motives might be a bit mixed up. South Korean military command does not want to start a war to defeat "evil commies": that would leave the whole peninsula in smoking ruins. We just had an idiot president who tried to take over the country in the stupidest means possible and failed.
[1] https://www.hani.co.kr/arti/society/society_general/1263280.... (article in Korean)