I feel the same way, I usually don't complain about some filler arcs of manhwas that I've read but this one, I don't know. It's just boring and the supporting characters are so dumb, even the director that Ijin is protecting is pretty dumb. How did she become a director in the first place if she can't even think about the common things and doesn't even have a single person she can trust around. This arc has like 0 interesting points and it seems to me is just to showcase Ijin's awesomeness against NPC's but come one, we as readers already knew that
I think you truly expressed what I'm also feeling regarding this feeler arc. I just didn't want to point out the details you mentioned coz my post would have been long. So I generalized my point and made it short.
Just like you, I don't normally complain but the chapters and the supporting characters of this arc pushed me to let out my feelings.
Maybe the author is using this filler arc as a way of coming up with a better storyline for the next arc. But, for my part, the spark of the mercenary enrollment story is a bit off in this arc. This is just how I feel about this arc. I hope they wrap it up fast and move on to better storylines.