
I mean he's not much of a loser per se since he was a red knight (not to mention one of the highest rank) in his previous life, so pretty much he has more experienced without the system and tbf he had every right to be arrogant since he was bullied by his peers and deemed as a weakling anyway so why not give them a show for his strength?
Pls don't be mad I'm just stating my opinion and I won't force you to continue to read

I like this storyline.
The main character was treated like shit growing up since he was weak. He was bullied, expelled and sold as a slave, leading him to fend for himself. He was weak willed growing up but he had to change and worked hard to gain confidence in himself and his skills (Absolute confidence in oneself is really difficult too achieve).
Anyway, years later he ended up getting killed. Due to some artifact, he ended up back in his 7 year old body with his 30ish years of memories intact. I dont know about you, but I sure as hell will still have my 30 year old personality and my trauma since memories shape who we are as a person. As such, this guy retained his personality and the confidence he build over the course of his previous life.
To be honest, he is not really an asshole or a showoff, I have read stories that makes his guy very vanilla. Anyway, most of these main characters had a shitty childhood who look like he is hiding in the shadows. Moreover, these main characters never bully the weak or look down on those trying to improve themselves. In concllusion, I think this is a good representation of these type of mc's.
Another regressed MC that was a loser in his past life then acts arrogant now that he has a cheat, will he continue to act like this? The cringe I get when he acts arrogant is just too much, I need a bit humbleness.