Agreed that they have a pretty big military in terms of raw numbers. I’m not going to discuss quality because the biggest question mark here is force projection.
How are they planning on sending over any significant manpower and supplies across 2800km?
They don’t even have a navy capable of circumnavigating the korean peninsula, much less make the trip to Ukraine or the wrong side of Russia.
They have 2 transport aircraft, the bigger of the 2 has a max passenger capacity of 44 pax. Neither of those have the range to get near Ukraine when flying fully fueled, nevermind if it were fully loaded.