The best move would be to retire the '96 born players this time and have Son Heung-min retire after the Asian Cup

Kim Min-jae has a high reputation, but as a defender, he is constantly involved in controversies and lacks defensive contribution compared to his name value.
Seeing how he can't say a word at Bayern Munich yet refuses to leave because he likes it there, we should just have him retire from the national team and let him stay permanently at Munich.
If the '96 born players and Son Heung-min all leave, the problem is Lee Kang-in.
Because his work rate is low, the team either has to run like crazy for him, or he is only useful for "click-and-go" counterattacks.
However, Korea is not a team with high work rates, nor do they have a lone striker who can execute those quick counterattacks.
It is already a well-known fact that in the national team, he ignores seniority and just does his own thing.
I believe the best option is to have even Lee Kang-in retire after the Asian Cup.