I thought it was a repetitive manga, and it is a bit at first, but as it goes on it gets really interesting, very well structured and I don't mind it at all. To be clear, I didn't just read 20 chapters like most people here, but up to chapter 182, you won't regret continuing it.
I find it a splendid story and it's much more interesting than I expected, I don't understand why it has such a low rating... I recommend you take a look at it
from here, however, we cannot know whether before the MC's departure, Leila already existed before or was created after her journey. She was introduced after MC returned, so maybe the timeline changed after her disappearance