As of my knowledge cutoff in October 2023, there are no reports indicating that South Korean investigators have attempted to arrest President Yoon Suk-yeol or that he has been impeached. President Yoon Suk-yeol assumed office in May 2022 and continues to serve as the leader of South Korea.
If there have been developments after October 2023, I recommend checking the latest news from reliable sources to obtain accurate and up-to-date information.
Reference(s):
cgtn.com