I agree. People have hate boner for it lol. Its good until final chapters. Simply because its generic doesn't mean its bad.
Whenever a series gets super popular, it's going to end up getting lots of hate as well. There is nothing wrong with not liking Demon Slayer or thinking it is overrated, but sometimes I agree that the hate goes too far and sometimes people love to hate on it just because of it's popularity and very high sales.
Not every series needs to be super deep or complex, there is nothing wrong with Demon Slayer being a simple series.
Imo I do enjoy the fights in Demon Slayer and I also do really like the characters as well, overall I do think Demon Slayer is a fun series to watch or read but I also agree that it isn't the best thing ever but I also don't think it's the worst either.