Honestly though, I think the first 20 chapters were used to set up the back stories for each character so you could be emotionally attached to them. Idk if it worked for you thought since u thought it was boring but I sure as hell enjoyed every chapter of this webtoon ヾ(☆▽☆)
I enjoyed it but it got a little boring for me because I didn't know when things would truly begin to happen and I was just excited to see her to finally become a delivery knight. That being said, I'd be willing to read 100 chapters like that in order to eventually see that happen since I like the webtoon so much.
I was getting a little bored in the beginning since things were too slow and stagnant for me BUT after around chapter 22(?) things REALLY took off. I felt my adrenaline pumping and the tension as if I was there. I also became invested in the stories of others, excluding the mc, which is usually hard for me to do since i don't give a crap about them.
All of the characters have very well developed personalities and depth and mc shows tremendous character growth. I've never read a webtoon like this since this kind of setting is more commonly seen in books. I HIGHLY RECOMMEND this for those that enjoy the dystopian and post-apocalyptic genre and for those who don't.