I dont like it when characters native to their own world dont understand their own power scales and rules.
If i saw someone fight a bear in real life and kill it my reaction wouldnt be "is that really strong? idk". I would have the same reaction if i was a 5 year old or a retired old man "that guy is motherfucking strong". The fact that after 17 years of living he had to be told what the average status in his world is and what is suposed to be considered a normal feat makes this whole chapter so jarring.
I guess thats one of the benefits of the isekai genre that people hate so much, main characters dont know the rules of the world they move to so it makes sense that they are all act as if it must be a mistake or not a big deal when they kill the dragon god or whatever.