"President Yoon has taken an overwhelmingly pro-US policy compared to previous presidents," and his "PPP is fiercely anti-communist and advocates a hawkish policy against North Korea" [1]. With "many PPP politicians support[ing] South Korea having nuclear weapons on its own," this is not the man Pyongyang or Moscow want as dicator in Seoul.
[1] https://en.wikipedia.org/wiki/People_Power_Party_(South_Kore...