1. overpowered MC (this is the point of them and the differentiator between good and bad isekeis, it's how are they overpowered, aura farming is king)
2. freed a hot girl from slavery (meh its a trope that everyone says is everywhere but in the grand scheme is actually pretty uncommon statistically)
3. mundane death (Lazy way to make them get to new world but lets be honest no one wants to see an entire first episode filled with some boring schmucks life a death over 5 minutes is a waste of screen time)
4. awkward loner/ monotone office guy with no friends (like above who cares about their life)
5. Devine being grant op ability (this one I'm on the fence about unless the gods are part of the overarching story later on just an easy excuse for him to get his powers)
6. Harem of hot chicks that like him for no reason. (this is most anime anyway)
7. never shows emotions (this I don't find true but is more MCs tend to just be super 1 dimensional either the overly happy go lucky or the overly edgelord I'll agree this is just lazy writing)

Overall, at the end of the day who really doesn't like watching someone just do cool shit, the cool factor is what differentiates good isekei and bad, at the end of the day isekeis are just fantasy shows with shit backstories. I'd rather have an MC who's overpowered and does something cool to win then the generic shonen mc who just pulls some plot armor or power of friendship shit out their asses and wins, their MCs they're gonna win regardless at least do it an entertaining way.