Review of The Rising of the Shield Hero

One word. Shit. In all honestly, the first 3 episodes were passable. I'm sure anyone reading this has seen an isekai since they get released 5 times a year like they're the McDonald's of anime but for the few that haven't, the start is the same, a socially awkward loser guy ends up getting trapped in a fantasy world. It seems to be common trope for said protagonist to become a complete Mary Sue in this new world, however I credit this anime for not falling into the same trap, or at least right off the bat. Naofumi and 3 other guys become heroes of thisworld, and while the others all have useful weapons like a spear, sword or bow, Naofumi is stuck with a shield. Everyone views him as the Yamcha/Sakura of this world and to make things worse for him, he gets falsely accused of being a rapist. To conclude, it begins as a promising underdog story.
Naofumi then buys a 5 year old cat girl named Raphtalia to be his slave and do all the fighting for him though for some reason she's 18 in the very next episode and proceeds to never age again throughout the series. Now the fourth episode is where things get bad. The spear hero disagrees with him owning a slave and challenges him to a duel, where he can free her if he wins. Despite being a much lesser person irl and having by far the worst class, Naofumi somehow wins this duel and thus gets rid of any reason for me to continue rooting for him as an underdog.
After this, the series becomes irredeemable. Asun- I meant Raphtalia becomes a loyal fangirl for Naofumi and you can't go 2 damn minutes throughout the rest of the series without hearing her cry "Naofumi-sama!" She becomes an annoying brat that caused an entire bar fight because one person dared say something remotely negative about her beloved Naofumi and she constantly begs him to never go back to his own world without considering in the slightest that maybe he has a family that misses him. Another fangirl, also joins him and has the ability to turn into a large bird. The spear hero from then on is portrayed as a bumbling idiot who get's kicked into the sky by the bird girl in almost every encounter he has with Naofumi again. Him and his female companion, Princess Myne, could honestly be replaced with Team Rocket from Pokemon and there will be virtually no difference. The series even starts trying to set up a romance between Naofumi and Raphtalia which is weird af given how he was still changing her diapers when they first met. I haven't watched season 2 nor read the LN but I pray they don't become a thing.